RASNZ Electronic Newsletter September 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 201

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Beatrice Hill Tinsley 2017 Lecture Tour
2. 2017 Burbidge Dinner - Auckland
3. Exploring Mars with 150,000 Earthlings - Wellington & Auckland
4. Third International Starlight Festival, 13-15 October
5. Great Barrier Island Now a Dark Sky Sanctuary
6. The Solar System in October
7. Starpath Game Wins Future Transport Competition
8. Variable Star News
9. New Supernova Analysis Reframes Dark Energy Debate
10. ASKAP Joins the Hunt for Fast Radio Bursts
11. Future Star Encounters
12. How to Join the RASNZ
13. Quotes

1. Beatrice Hill Tinsley 2017 Lecture Tour

The RASNZ Lecture Trust Inc. is pleased to announce that the 2017 Beatrice Hill Tinsley Lecturer is Dr. Natalie Batalha. The lecture tour will be held during October and will include appearances at the Starlight Festival at Mt Cook village (13-15 October) and lectures at venues through the country. See places and times below.

Dr. Natalie Batalha is an astrophysicist at NASA Ames Research Center and the Mission Scientist for NASA's Kepler Mission. She has been involved with the Kepler Mission since the proposal stage and has contributed to many different aspects of the science, from studying the stars themselves to detecting and understanding the planets they harbour. She led the analysis that yielded the discovery in 2011 of Kepler-10b ? the mission's first confirmation of a rocky planet outside our solar system. Today, she leads the effort to understand planet populations in the galaxy based on Kepler discoveries. In 2011, Dr. Batalha was awarded a NASA Public Service Medal for her vision in communicating Kepler science to the public and for outstanding leadership in coordinating the Kepler Science Team. In 2015, she joined the leadership team of NASA's Nexus for Exoplanet System Science (NExSS). NExSS brings teams from multiple disciplines together to understand the diversity of worlds and will lead NASA's efforts to understand which are most likely to harbour life.

Dr. Batalha's Lecture Title and Synopsis A Planet for Goldilocks: The Search for Evidence of Life Beyond Earth

"Not too hot, not too cold" begins the prescription for a world that's just right for life as we know it. Finding evidence of life beyond Earth is one of the primary goals of science agencies around the world thanks in large part to NASA's Kepler Mission which launched in 2009 with the objective of finding Goldilocks planets orbiting other stars like our Sun. The space telescope opened our eyes to the terrestrial-sized planets that populate the galaxy as well as exotic worlds unlike anything that exists in the solar system. The mission ignited the search for life beyond earth via remote detection of atmospheric biosignatures on exoplanets. Most recently, our collective imagination was awakened by the discovery of Goldilocks worlds orbiting some of the nearest neighbours to the Sun, turning abstractions into destinations. Dr. Batalha will give an overview of the science legacy of the Kepler Mission and other key discoveries. She'll give a preview of what's to come by highlighting the missions soon to launch and those that are concepts taking shape on the drawing board.

Lecture venues and times

Auckland, Friday October 6, 7pm, Lecture theatre OGGB4, Level 0, Owen G Glenn Building, The University of Auckland, 12 Grafton Road. Register for this free event at nataliebatalha.eventbrite.co.nz

Whangarei October 7, 7:00pm, Tikipunga High School Hall. Admission: Adults $10, Child $5. Bookings: www.planets.nz

Gisborne October 9, 7:00pm, War Memorial Theatre, 159 Bright Street, Gisborne. Admission: Adult $10, Child $5 (under 15).

Palmerston North October 10, 7:30pm, Community Leisure Centre, Ferguson Street, Palmerston North. Gold coin admission.

Christchurch Wednesday October 11, 07:30 pm. Lecture Theatre A1, Canterbury University, Ilam, Christchurch. No admission charge.

Invercargill October 18, 7:30pm, The Ascot Park Hotel, Admission: Adult & S.I.T. Students $5.00, School Students $2.00.

Dunedin October 19, Hutton Theatre, Otago Museum at 5:30 pm. No admission charge.

-- Mostly from http://rasnz.org.nz/rasnz/beatrice-hill-tinsley-lectures

2. 2017 Burbidge Dinner - Auckland

Date: Saturday, 7th October 2017 Venue: Ellerslie Events Centre, Guineas 3 room Start Time: 7:00pm (doors open at 6:30pm)

Tickets: $65 pp. Includes a buffet dinner. Ticket can be booked:

  • by email at This email address is being protected from spambots. You need JavaScript enabled to view it.
  • by phone to Niven on 021 935 261 or Bill on 021 225 8175.

Our guest speaker this year is: Dr Meg Schwamb, Assistant Scientist at the Gemini Observatory's Northern Operations Center in Hilo, Hawai'i. Her talk will be:

Archaeology of the Outer Solar System

Pluto resides beyond Neptune orbiting in a sea of small icy bodies known as the Kuiper belt. These distant objects are truly the fossil relics left over after our Solar System's formation. Digging into the orbits, dynamics, and physical properties of these bodies, provides new insights and windows into the origins and past history of the outer Solar System. This includes hints of a possibly unseen planet, or an event long-since erased from the rest of the Solar System.

In this talk, we'll explore the changing views of the outer Solar System from the discoveries of ground-based surveys to the New Horizons fly-by of the Pluto System.

This talk will not be technical and is suitable for a general audience. Meg Schwamb is a planetary scientist and astronomer studying the bodies in our Solar System and beyond. She currently is an assistant scientist at the Gemini Observatory based in Hilo, Hawai'i. Meg's research focuses on how planets and their building blocks form and evolve, applying ground-based surveys to probe our Solar System's small body reservoirs. Later on this year, Meg will receive the Carl Sagan Medal for Excellence in Public Communication in Planetary Science from the American Astronomical Society's Division for Planetary Science.

As well as our guest speaker there will be the prize giving for the Astrophotography Competition including the Harry Williams Trophy for the supreme winner, and the Beaumont Writing Prize. A spectacular venue, great meal, cash bar and ample free parking.

-- Jonathan Green

3. Exploring Mars with 150,000 Earthlings - Wellington & Auckland

Astronz and the Wellington Astronomical Society are hosting a public talk by Meg Schwamb from the Gemini Observatory at 6:30pm on Tuesday 10th October. For venue details see the Wellington Astronomical Society's webpage or Facebook page

This talk will also be given in Auckland on 9th October as the Auckland Astronomical Society monthly meeting.

The Red Planet is a dynamic world. Mars' south pole is sculpted by the never-ending cycle of freezing and thawing of exposed carbon dioxide ice. In the summer, carbon dioxide jets loft dust and dirt through cracks in the thawing carbon dioxide ice sheet to the surface where winds blow the material into the hundreds of thousands of dark fans observed from orbit. This process is completely alien, with no Earthly counterpart. Understanding the direction, frequency, and appearance of these fans (a proxy for the jets) and how varying factors impact these properties, we can better understand the Martian climate and how it differs from Earth.

It is difficult if not impossible for computer algorithms to accurately identify individual fans. Computers just aren't good enough to do the required task, but the fans spotted for orbit are easily spotted by the human eye. I will talk about the Planet Four and Planet Four: Terrains projects and its on-going effort collaborating with over 150,000 people around the world through power of the Internet. Volunteers map the dark seasonal fans and other surface features carved during by the carbon dioxide gas jets. I will present the discoveries made by these citizen scientists and discuss how you can get involved in exploring Mars from the comfort of home.

See above, Item 2, for a synopsis on Meg Schwamb.

-- Thanks to Andrew Buckingham.

4. Third International Starlight Festival, 13-15 October

The Third International Starlight Festival will be held at the Hermitage, Mt Cook over three days in 2017, 13-15 October.

The Festival will celebrate the Aoraki Mackenzie International Dark Sky Reserve (www.darkskyreserve.org.nz) whose mission is to encourage and protect dark skies free of light pollution in the Mackenzie, and to promote star gazing and astro-tourism. We do this by organizing a Starlight Festival every second year for the benefit of the public and international tourists. Astro-tourism in the Mackenzie at Tekapo and Mt Cook is now one of New Zealand?s biggest tourist attractions, with about 200,000 people coming to Tekapo annually, many from Asia and Europe, to see the stars.

The 2017 Festival will be our third, after very successful events in 2013 in Tekapo and 2015 at Twizel. The Festival will be a mixture of events including lectures, workshops, exhibitions, videos and documentaries, planetarium shows and of course, star-gazing. We have engaged three world-class speakers to come to Mt Cook for the Festival. They are:

? Dr Natalie Batalha NASA Ames space scientist, Moffett Field (near San Francisco), California. (Time Magazine in April 2017 named her as one of the 100 most influential people on the planet). She will talk about ?A Planet for Goldilocks? and the search for habitable Earth-like planets ? Kevin Govender, Director of the Office of Astronomy for Development of the International Astronomical Union, based in Cape Town, South Africa. He will talk about ?Astronomy for Humankind?. ? Sze-leung Cheung, Director of the Office of Astronomy Outreach of the International Astronomical Union, based in Tokyo, Japan. He will talk about ?The threat of LEDs to astronomy and how to build a dark-sky-friendly future?.

All three are outstanding speakers, and Sze-leung Cheung is fluent in Chinese as well as English, so can give his talk in both languages to attract overseas tourists.

More details on the Third Starlight Festival and our keynote speakers are at www.starlightfestival.org.nz. On-line ticket sales will be available from mid-July. The website also has all accommodation options in and near Mt Cook.

Mark Gee from Wellington will show some of his stunning night-sky time-lapse animations and on the morning of Oct 14 will conduct an astro-photography workshop for everyone wanting to learn these techniques. Steve Chadwick from Palmerston North will show his amazing night sky animations and photography, as will also the renowned Fairlie and Tekapo astrophotographer, Fraser Gunn.

There is also an astro-photography exhibition with nine of New Zealand?s top astro-photographers exhibiting their images. The Festival features videos, exhibitions, workshops, planetarium shows and stargazing (at the new Mt Cook Observatory) over three days, 13-15 October.

-- John Hearnshaw, Chair, Aoraki Mackenzie International Dark Sky Reserve Board.

5. Great Barrier Island Now a Dark Sky Sanctuary

Great Barrier Island has become the world's first island to be recognised as a Dark Sky Sanctuary. On Saturday August 19 a quarter of the its 1000-strong population turned out to bask in the starry glow of a unique global status.

The outer Hauraki Gulf island - located 90 kilometres north-east of Auckland - has no mains electricity, and has now been recognised for its star-gazing credentials by the International Dark-Sky Association (IDA). Only two other locations in the world are considered Dark Sky Sanctuaries: Chile's Gabriela Mistral and the Cosmic Campground in the US state of New Mexico. Great Barrier stands out as the only such sanctuary to comprise an entire island.

Residents Gendie and Richard Somerville-Ryan worked with an Auckland astronomer to prove Great Barrier deserved its official accolade. "We had the right place for it, a remote, pristine environment that's off the grid. It was the right time for us to ensure we protected the dark sky, and we had the right people," Richard said.

Great Barrier Local Board Chair Izzy Fordham said Auckland-based astronomers brought over telescopes for the islanders to view. There was a long list of acknowledgements to those who helped the island's IDA application, Fordham said.

"We've had incredible support from the community along the way and so many others who have got behind this. "Sanctuary status is reserved for the most isolated, and dark locations in the word and this designation is specifically designed to increase awareness of fragile sites and promote their long-term conservation." Because of its relative isolation compared to the South Island's popular Tekapo star-gazing site, Great Barrier could benefit from "boutique style tourism" keeping its unspoilt environment, Fordham said.

Auckland Mayor Phil Goff and Great Barrier Island MP Nikki Kaye helped mark the occasion as around 250 residents celebrated at the Claris Sports Club. Goff said the islanders' "hard work has brought us together to celebrate a great moment in Auckland's history".

What makes for dark sky status? The International Dark-Sky Association (IDA) lays-out three criteria:

  • An area has to have "exceptional or distinguished quality of starry nights and a nocturnal environment that is protected for its scientific, natural, or educational value, its cultural heritage and/or public enjoyment".
  • Sanctuaries must typically be "situated in a very remote location with few (if any) nearby threats to the quality of its dark night skies and it does not otherwise meet the requirements for designation as a park or reserve".
  • A sanctuary's designation is "designed to increase awareness of these fragile sites and promote their long-term conservation".

-- Copied from Simon Maude's article on the Stuff website at https://www.stuff.co.nz/science/95959306/great-barrier-island-recognised-as-a-dark-sky-sanctuary

6. The Solar System in October

Sunrise, Sunset and Twilight Times in October

Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

                    October  1  NZDT               October 31  NZST
       SUN: rise: 6.53am,  set: 7.28pm    rise:  6.06am,  set: 8.02pm
Twilights     morning       evening          morning       evening
Civil:    starts: 6.28am, ends: 7.54pm   starts: 5.48am, ends: 8.30pm
Nautical: starts: 5.55am, ends: 8.27pm   starts: 5.04am, ends: 9.07pm
Astro:    starts: 5.22am, ends: 9.01pm   starts: 4.25am, ends: 9.46pm

October Phases of the Moon (times NZST, as shown by GUIDE)

          Full moon:     October  6 at  9.40 am (Oct  5, 18:40 UT)
  Last quarter   October 13 at  1.26 am (Oct 12, 12:26 UT)
  New moon:      October 20 at  8.12 am (Oct 19, 19:12 UT)
  First quarter: October 28 at 11.22 am (Oct 27, 22:22 UT)

The Planets in October 2017

Four of the five naked eye planets will be close to the Sun during October. During the month Mercury reaches superior conjunction and Jupiter is at conjunction on the 27th. On the other hand Uranus is at opposition on the 20th. Saturn is the only naked eye planet readily visible - unless you can spot Uranus at magnitude 5.7.

MERCURY is at superior conjunction at the far side of the Sun on October 9, NZ time. Following conjunction the planet will become an evening object setting after the Sun. By the end of the month Mercury that will be an hour and a quarter later than the Sun. The planet, at magnitude -0.4, could just be visible some 45 minutes after sunset but very low at an altitude of 4.5° in a direction between midway between west and northwest.

VENUS is a very low morning object during October. On the 1st it rises 50 minutes before the Sun, by the 31st this will have reduced to just over 30 earlier. It will be about 4.5° up and to the east just before sunrise. On the morning of the 6th there is a close conjunction of Venus and Mars. The problem is that Venus will be only some 3° up at the start of civil twilight. If you have a good horizon to the east, Venus, Magnitude -3.9, should then be visible a little north of east. Mars will be only 12 arc minutes away, one-fifth of a degree almost directly above Venus. At magnitude 1.8 it is doubtful if it will be visible by eye, but binoculars should show it up.

MARS, now a morning object, rises 45 minutes before the Sun on October 1 and just over 70 minutes before the Sun on the 31st as its angle from the Sun increases. This will make it a little more visible, but it will be only some 6° up at 5.30 am in Wellington. By then Mars will be 15° from Venus. Mars starts October in Leo and moves into Virgo on October 12.

JUPITER starts October in the evening sky. On the 1st, half an hour after sunset, it will be some 11° up almost due west. Spica will be 5° away to the lower left of the planet. Better views May be obtained a little while later, but Jupiter will set about 100 minutes after the Sun.

The planet will get steadily lower in the early evening sky during October to eventually get lost in twilight. Jupiter reaches conjunction with the Sun on the 27th, it will then be 963 million km, 6.43 AU, from the Earth and 5.44 AU beyond the Sun.

SATURN is readily visible in the evening sky during October although by the end of the month it will set a few minutes before midnight. The planet is in Ophiuchus moving away from Antares. The crescent moon passes Saturn on the evening of October 24. At 10 pm the two will be just over 4° apart with the moon below and to the right of Saturn. The magnitude 2.5 star eta Oph will be a similar distance away directly below the moon.

Outer Planets

URANUS is at opposition on the night of October 19/20 NZ time. The actual opposition is close to the time of the new moon. Uranus will be at its brightest, magnitude 5.7, and so May be visible to the naked eye from a dark sky site. Good eyesight will be needed.

NEPTUNE is also in the evening sky at magnitude 7.8 in Aquarius. On the night of October 3/4 the moon will occult Neptune for viewers in New Zealand. Times range from 12:16 at Invercargill to 12:42 at Auckland The moon will be near full, 94% lit, but the event should be visible with a modest telescope given Neptune's 7.8 magnitude.

The occultation will occur just a little north of centre on the moon unlit limb. The event will not be instantaneous, the disk of Neptune taking some 6.2 seconds to disappear completely.

Minor Planets

(1) CERES is a morning object in Cancer. It starts October at magnitude 8.8 and brightens slightly during the month to magnitude 8.6. (2) PALLAS is in Eridanus most of October but moves into Fornax on the 28th. During the month it brightens a little from magnitude 8.5 to 8.2. (7) IRIS is in Aries throughout October, brightening from magnitude 7.7 to 6.9 during the month, making it the brightest asteroid all month.

-- Brian Loader

7. Starpath Game Wins Future Transport Competition

In August a team of Riccarton High School students won the Y7-10 Best Game category in the nationwide Future Transport competition run by the New Zealand Transport Authority.

The Year 9 team developed a board game to inform users about an initiative using ?starpath pro? which is a sprayable coating that gives pathways an artificial glow at night which makes it safer for walkers and reduces need for lighting.

The team worked during term 2 on this as part of a collaborative project co-facilitated by their math and science teachers. As part of this the team had to provide evidence that they investigated transport challenges, developed solutions and connected with the community as well as produce the playable game itself.

The judges were impressed with their excellent documentation, in depth play testing and top notch design process. The students won $4000 in vouchers for the school and themselves as well as an article featuring their winning entry in an upcoming Interface magazine.

A video showcasing Starpath can be viewed at http://education.nzta.govt.nz/competition/winners-games

-- From a note forwarded by Karen Pollard from the Riccarton High School newsletter.

Steve Butler of the RASNZ Dark Skies Group adds: It is great to see the next generation adopting the idea of using less light at night. The game is also an interesting way to spread the word.

As it happens... at the launch of the Great Barrier Island International Dark Sky Sanctuary they had an Expo with displays related to astronomy or dark skies. One of the displays was by a New Zealand supplier of Starpath! He had samples of the path sealing product as well as Eco Discs which are glow in the dark disks which can be fixed down to define the edge of pathways. Cheaper that the full seal coating. I will bring two sample disks and a brochure to Mt Cook for the Festival.

Their website is: www.nevanadesigns.com The local agent is Wayne Renner, This email address is being protected from spambots. You need JavaScript enabled to view it., 021 688 946. He is based in Tauranga.

8. Variable Star News

Since about 2010 the American Association of Variable Star Observers (AAVSO) has been running an All Sky Automated Photometric Survey (APASS). A description of this survey has been posted recently on the AAVSO home page under the heading Recent Activity.

Through grants from the Robert Martin Ayers Sciences Fund and the AAVSO Endowment Fund, the AAVSO is performing an all-sky photometric survey. This survey is conducted in five filters: Johnson B and V, plus Sloan g?, r?, i?. It is valid from about 7th magnitude to about 17th magnitude. Precise, reliable standardized photometry in this magnitude range is in high demand, both from our observers and from the professional community. Such a catalogue allows many research programs to quickly establish transformation between systems and efficiently achieve conversion of photometry to more fundamental physical properties. It will bridge the gap between Tycho2 and Sloane Digital Sky Survey, plus cover the entire sky at the same depth as the UCAC catalogue published by US Naval Observatory. The survey will take approximately one more year to complete. Data release 1 of APASS occurred on 2010 September 10. Since then the southern sky has been surveyed and this exercise May have benefitted from knowledge developed in the initial surveys.

The current Data Release version is DR 9 (29 July 2015). The article posted includes a history of the development work, documents limitations in the data acquisition processes and gives hints on using the data. Address https://www.aavso.org/ Home page ? Recent Activity.

-- Alan Baldwin

9. New Supernova Analysis Reframes Dark Energy Debate

The accelerating expansion of the Universe May not be real, but could just be an apparent effect, according to new research published in the journal Monthly Notices of the Royal Astronomical Society. The new study?by a group at the University of Canterbury in Christchurch, New Zealand?finds the fit of Type Ia supernovae to a model universe with no dark energy to be very slightly better than the fit to the standard dark energy model.

Dark energy is usually assumed to form roughly 70% of the present material content of the Universe. However, this mysterious quantity is essentially a place-holder for unknown physics.

Current models of the Universe require this dark energy term to explain the observed acceleration in the rate at which the Universe is expanding. Scientists base this conclusion on measurements of the distances to supernova explosions in distant galaxies, which appear to be farther away than they should be if the Universe?s expansion were not accelerating.

However, just how statistically significant this signature of cosmic acceleration is has been hotly debated in the past year. The previous debate pitted the standard Lambda Cold Dark Matter (?CDM) cosmology against an empty universe whose expansion neither accelerates nor decelerates. Both of these models though assume a simplified 100 year old cosmic expansion law ? Friedmann's equation.

Friedmann's equation assumes an expansion identical to that of a featureless soup, with no complicating structure. However, the present Universe actually contains a complex cosmic web of galaxy clusters in sheets and filaments that surround and thread vast empty voids.

Prof David Wiltshire, who led the study from the University of Canterbury in Christchurch, said, ?The past debate missed an essential point; if dark energy does not exist then a likely alternative is that the average expansion law does not follow Friedmann's equation.?

Rather than comparing the standard ?CDM cosmological model with an empty universe, the new study compares the fit of supernova data in ?CDM to a different model, called the ?timescape cosmology?. This has no dark energy. Instead, clocks carried by observers in galaxies differ from the clock that best describes average expansion once the lumpiness of structure in the Universe becomes significant. Whether or not one infers accelerating expansion then depends crucially on the clock used.

The timescape cosmology was found to give a slightly better fit to the largest supernova data catalogue than the ?CDM cosmology. Unfortunately the statistical evidence is not yet strong enough to rule definitively in favour of one model or the other, but future missions such as the European Space Agency?s Euclid satellite will have the power to distinguish between the standard cosmology and other models, and help scientists to decide whether dark energy is real or not.

Deciding that not only requires more data, but also better understanding properties of supernovae which currently limit the precision with which they can be used to measure distances. On that score, the new study shows significant unexpected effects which are missed if only one expansion law is applied. Consequently, even as a toy model the timescape cosmology provides a powerful tool to test our current understanding, and casts new light on our most profound cosmic questions.

-- Press release from the Royal Astronomical Society (U.K.). See it with images at https://www.ras.org.uk/news-and-press/3046-new-supernova-analysis-reframes-dark-energy-debate

10. ASKAP Joins the Hunt for Fast Radio Bursts

A new telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), has joined the search for energetic and elusive fast radio bursts (FRBs). And in just a few days of looking, it?s already had success!

FRBs are mysterious millisecond-duration radio pulses that were first discovered around a decade ago. Since that time ? particularly in recent years ? we?ve made some progress toward the goal of localizing them. We?re now fairly convinced that FRBs come from outside of the galaxy, and yet they?re enormously bright ? orders of magnitude more luminous than any pulse seen from the Milky Way.

Better identification of where these mysterious bursts come from would help us to determine what they are. But so far, we?ve discovered only around 30 such bursts, despite the fact that they?re estimated to occur at a rate of ~3,000 events per day across the whole sky.

They are hard to find due to their short duration. Effective detection would require instantaneous coverage of a very large fraction of the sky. The Parkes radio telescope ? which has detected all but five of the fast radio bursts published to date ? has a field of view of 0.6 square degrees, significantly limiting our ability to rapidly survey for these transients.

ASKAP is a wide-field radio telescope made up of an array of 12-meter antennas. Using phased-array-feed technology, it is able to instantaneously observe an effective area of 160 square degrees ? an enormous field compared to Parkes?s! This capability significantly increases our chances of being able to detect fast radio bursts.

In a new study led by Keith Bannister (Australia Telescope National Facility, CSIRO Astronomy and Space Science), a team of scientists presented results from ASKAP?s first 3.4-day pilot survey. Bannister and collaborators announced that, in this brief time, ASKAP detected a fast radio burst: FRB 170107, an especially luminous, ~2 millisecond burst. It confirms the presence of an ultra-bright population of FRBs.

The discovery and characterization of a burst already after such a short initial campaign suggests that ASKAP will become a very powerful tool for detecting FRBs ? including some of the rarest bursts, ultra-bright ones like FRB 170107. Using the multiple bands of ASKAP, the authors were able to constrain the position of FRB 170107 to a region just 8? x 8? in size. No known field galaxies exist in that region, so we?re still not sure exactly where it came from, but this localization is already a significant achievement.

-- Abridged from the American Astronomical Society's 'Nova' of 24 May 2017. Citation: K. W. Bannister et al 2017 ApJL 841 L12. doi:10.3847/2041-8213/aa71ff See http://www.skyandtelescope.com/astronomy-news/askap-joins-the-hunt-for-mysterious-bursts/ for images and other citations.

11. Future Star Encounters

The movements of more than 300 000 stars surveyed by the European Space Agency's (ESA's) Gaia satellite reveal that rare close encounters with our Sun might disturb the cloud of comets at the far reaches of our Solar System, sending some towards Earth in the distant future.

As the Solar System moves through the Galaxy, and as other stars move on their own paths, close encounters are inevitable ? though 'close' still means many trillions of kilometres.

A star, depending on its mass and speed, would need to get within about 60 trillion kilometres or 400 000 AU before it starts to have an effect on the Solar System's distant reservoir of comets, the Oort Cloud, which is thought to extend out to 100 000 AU. For comparison, the outermost planet Neptune orbits at an average distance of about 4.5 billion kilometres, or 30 AU. (One Astronomical Unit (AU) is the Sun?Earth distance. One light-year is 63 240 AU. Alpha Centauri, the closes naked-eye star, is 270 000 AU away.)

The gravitational influence of stars that pass near the Oort Cloud could perturb the paths of comets residing there, jolting them onto orbits that bring them in to the inner Solar System. While this is thought to be responsible for some of the comets that appear in our skies, it also has the potential to put comets on a collision course with Earth or other planets.

Understanding the past and future motions of stars is a key goal of Gaia as it collects precise data on stellar positions and motions over its five-year mission. After 14 months, the first catalogue of more than a billion stars was recently released, which included the distances and the motions across the sky for more than two million stars.

By combining the new results with existing information, astronomers began a detailed, large-scale search for stars passing close to our Sun. So far, the motions relative to the Sun of more than 300 000 stars have been traced through the Galaxy and their closest approach determined for up to five million years in the past and future. Of them, 97 stars were found that will pass within one million AU, while 16 come within about 400 000 AU.

A particularly close encounter of one star, Gliese 710, in 1.3 million years' time, stands out. Thanks to the Gaia data it is predicted to pass around 16 000 AU from the Sun, well within the Oort Cloud. Furthermore, although Gliese 710 has a mass of 60% that of our Sun, it travels much slower than most stars: nearly 14 km/s (50 000 kph) compared with the average 28 km/s. The speed of its passage means it will have plenty of time to exert its gravitational influence on bodies in the Oort Cloud, potentially sending showers of comets into the Solar System. During its close approach Gliese 710 will be the brightest star in the night sky.

Importantly, the latest study used Gaia measurements to make a general estimate of the rate of stellar encounters, taking into account uncertainties such as stars that might not have been included in the previous catalogues. For 5 million years in the past and into the future, the overall encounter rate is estimated to be around 550 stars per million years coming within one million AU or 16 light-years, of which about 20 would come closer than 3.2 light-years. That equates to about one potential 'close' encounter every 50 000 years or so.

These estimates will be refined with future Gaia data releases. The second is scheduled for next April, containing the information for about 20 times as many stars, and many more distant stars as well, allowing reconstructions up to 25 million years into the past and future.

Reference: "The completeness-corrected rate of stellar encounters with the Sun from the first Gaia data release," by C.A.L. Bailer-Jones, published in Astronomy & Astrophysics.

-- From an ESA press release at: http://sci.esa.int/gaia/59435-close-encounters-of-the-stellar-kind/

12. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2017 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

13. Quotes

"In order to arrive at what you do not know
You must go by a way which is the way of ignorance."
-- T.S. Eliot, 'Four Quartets, East Coker'.
"Not every mistake is a foolish one." -- Cicero.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
P.O. Box 57 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand

September 2017

Log in or become an RASNZ member to access this Southern Stars issue.

Southland Observatory 1972 - 2017
R W Evans
Volume 56, number 3. September 2017. p3

 

A Report on the Status of Stephen Carkeek’s Observatory at Featherston: The Oldest Surviving Astronomical Observatory in New Zealand
Gordon Hudson, Wayne Orchiston
Volume 56, number 3. September 2017. p6

 

Aurora Australis 1979 to 2016
R W Evans
Volume 56, number 3. September 2017. p11

 

Chariklo Occultation March 18, 2017
Gordon Hudson, Roland Idaczyk
Volume 56, number 3. September 2017. p12

 

6 Day Moon
Maurice Collins
Volume 56, number 3. September 2017. p14

 

AR12665: ‘Unlikely Hero!”
Harry Roberts
Volume 56, number 3. September 2017. p15

 

Book Review
Maurice Collins
Volume 56, number 3. September 2017. p18

 


RASNZ Electronic Newsletter August 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 200

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Harry Williams Astrophotography Competition
2. Third International Starlight Festival, 13-15 October
3. The Solar System in September
4. (3122) Florence Fly-By
5. Safe Solar Eclipse Viewing
6. Auckland Astronomical Society on YouTube
7. Variable Star News
8. Asteroid Moon Discovered By Amateur Astronomers
9. Cassini's Last Looks at Saturn
10. Brown Dwarfs Common?
11. Life-Building Chemical Found Around Young Stars
12. Mt John History Price Reduced
13. How to Join the RASNZ
14. Gifford-Eiby Lecture Fund
15. Quotes

1. Harry Williams Astrophotography Competition

Calling all Astrophotographers, the 2017 Harry Williams Astrophotography Competition is now open for entries, this year our judge is world-renowned planetary photographer Damian Peach, in 2010, Damian became the only Briton to win the prestigious Astronomy Photographer of the Year Award for his composite photograph of Jupiter's moons, Ganymede and Io, orbiting the stormy surface of the Gas Giant.

Damian is arguably the world's most well-known planetary photographer, his high resolution images of the planets have been compared in quality to the kind of images captured by orbiting spacecraft! So we are truly lucky to have Damian on board as our judge for this year's competition.

As in previous years we are lucky to have Australian Sky & Telescope on board as sponsors of both the Solar System category and the Miscellaneous / Artistic category, the winners of these categories will receive a one year subscription to the magazine as well as the usual cash prize. More sponsors to be announced soon.

The competition cut-off date is the 31st of August and the competition awards will be announced at the annual Burbidge dinner which is the Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.

The competition rules and entry forms can be found on the Auckland Astronomical Society website http://www.astronomy.org.nz/new/public/default.aspx

-- From the above website

2. Third International Starlight Festival, 13-15 October

The Third International Starlight Festival will be held at the Hermitage, Mt Cook over three days in 2017, 13-15 October.

The Festival will celebrate the Aoraki Mackenzie International Dark Sky Reserve (www.darkskyreserve.org.nz) whose mission is to encourage and protect dark skies free of light pollution in the Mackenzie, and to promote star gazing and astro-tourism. We do this by organizing a Starlight Festival every second year for the benefit of the public and international tourists. Astro-tourism in the Mackenzie at Tekapo and Mt Cook is now one of New Zealand´s biggest tourist attractions, with about 200,000 people coming to Tekapo annually, many from Asia and Europe, to see the stars.

The 2017 Festival will be our third, after very successful events in 2013 in Tekapo and 2015 at Twizel. The Festival will be a mixture of events including lectures, workshops, exhibitions, videos and documentaries, planetarium shows and of course, star-gazing. We have engaged three world-class speakers to come to Mt Cook for the Festival. They are:

o Dr Natalie Batalha NASA Ames space scientist, Moffett Field (near San Francisco), California. (Time Magazine in April 2017 named her as one of the 100 most influential people on the planet). She will talk about `A Planet for Goldilocks´ and the search for habitable Earth-like planets o Kevin Govender, Director of the Office of Astronomy for Development of the International Astronomical Union, based in Cape Town, South Africa. He will talk about `Astronomy for Humankind´. o Sze-leung Cheung, Director of the Office of Astronomy Outreach of the International Astronomical Union, based in Tokyo, Japan. He will talk about `The threat of LEDs to astronomy and how to build a dark-sky-friendly future´.

All three are outstanding speakers, and Sze-leung Cheung is fluent in Chinese as well as English, so can give his talk in both languages to attract overseas tourists.

More details on the Third Starlight Festival and our keynote speakers are at www.starlightfestival.org.nz. On-line ticket sales will be available from mid-July. The website also has all accommodation options in and near Mt Cook.

Mark Gee from Wellington will show some of his stunning night-sky time-lapse animations and on the morning of Oct 14 will conduct an astro-photography workshop for everyone wanting to learn these techniques. Steve Chadwick from Palmerston North will show his amazing night sky animations and photography, as will also the renowned Fairlie and Tekapo astrophotographer, Fraser Gunn.

There is also an astro-photography exhibition with nine of New Zealand´s top astro-photographers exhibiting their images. The Festival features videos, exhibitions, workshops, planetarium shows and stargazing (at the new Mt Cook Observatory) over three days, 13-15 October.

-- John Hearnshaw, Chair, Aoraki Mackenzie International Dark Sky Reserve Board.

3. The Solar System in September

NZDT starts at 2am on the morning of September 24 when clocks should be advanced by 1 hour, bringing NZ time to UT + 13 hours. Dates and times shown are NZST (UT + 12 hours) until September 23 and then NZDT for the rest of the month, unless otherwise stated. The southern spring equinox is on September 23, NZ time, with the Sun crossing the celestial equator at about 8am.

Sunrise, Sunset and Twilight Times in September

Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

                   September  1  NZST             September 30  NZDT
       SUN: rise: 6.43am,  set: 5.58pm    rise:  6.54am,  set: 7.27pm
Twilights     morning       evening          morning       evening
Civil:    starts: 6.18am, ends: 6.24pm   starts: 6.29am, ends: 7.53pm
Nautical: starts: 5.46am, ends: 6.56pm   starts: 5.57am, ends: 8.26pm
Astro:    starts: 5.15am, ends: 7.28pm   starts: 5.23am, ends: 8.59pm

September Phases of the Moon (times NZST, as shown by GUIDE)

          Full moon:     September  6 at  7.03 pm (07:03 UT)
  Last quarter   September 13 at  6.25 pm (06:25 UT)
  New moon:      September 20 at  5.30 pm (05:30 UT)
  First quarter: September 28 at  3.54 pm (02:54 UT)

The Planets in September 2017

The three terrestrial planets, Mercury, Venus and Mars, are all morning objects rising shortly before the Sun. Venus should be observable, especially early in the month. Mercury and Mars are not likely to be observable at any time.

VENUS starts the month rising nearly an hour and a half before the Sun. Half an hour before sunrise it will be some 9° up so easily visible as a low brilliant object. It will be well round to the north from east. The planet gets closer to the Sun as September progresses, so that by the 30th it will rise 50 minutes before the Sun. As a result, Venus will be then very low shortly before the Sun rises, and not as far to the north of east as at the beginning of the month.

In the middle of the month the three terrestrial planets will form quite a tight group in Leo fairly close to Regulus. On the 18th they are joined by the Moon. In a period of just under 24 hours, the Moon will occult Venus, Regulus, Mars and Mercury as seen from some part of the Earth. The Venus event is visible, as a daytime event, from all of Australia and New Zealand. At Wellington the time of disappearance is about 1:27 pm and the reappearance at 2:40 pm. The moon will be only a 6% lit crescent about 28° from the Sun. Binoculars are likely to show up the event, but the very thin crescent moon May be difficult to find. [Be sure to use binoculars from a shaded location so not to accidentally look at the Sun. - Ed.]

JUPITER is visible in the early evening during September. It sets three and a half hours later than the Sun on the 1st, about 100 minutes later on the 30th so by then will be a low object to the west following sunset. Jupiter is in Virgo, close to Spica. At their closest on the 12th, the 1st magnitude star will be 3° to the left of the planet. On the 22nd, the crescent moon will join the pair, when it will be just over 4° to the lower right of Jupiter. By then it would be best to be looking by 7pm or soon after. An hour later the three will be very low.

SATURN is visible all evening during September, although it will set about 1.40 am NZDT on the 30th. Saturn will be in Ophiuchus. Its encounter with the moon will be on the 27th, the moon being a day short of first quarter, about 5° to the right of Saturn mid evening.

OUTER PLANETS URANUS rises just before 10pm NZST on the 1st and close to 9 pm on the 30th. The planet is in Pisces at magnitude 5.7 throughout the month.

NEPTUNE rises close to the time of sunset on September 1. By the 30th it will rise just after 5pm NZDT over 2 hours before the Sun sets. So it will then be well placed for viewing in the evening sky. The planet is in Aquarius at magnitude 7.8.

PLUTO, magnitude 14.4, remains in Sagittarius. It will be just under a degree from the 2.9 magnitude star pi Sgr.

MINOR PLANETS (1) CERES, a morning object starts the month at magnitude 9.0 in Gemini. On the 18th it will cross into Cancer brightening slightly during the month to magnitude 8.8.

(2) PALLAS is in Eridanus rising at 10.20 pm on the 1st. During September it brightens from magnitude 9.0 to 8.5.

(7) IRIS is in Aries throughout September, brightening from magnitude 8.5 to 7.7 during the month. It rises at 11:12 pm on the 1st and 10.33 pm on the 30th. It is quite close to Hamal, alpha Ari magnitude 2.0. Their separation is 2.1° on the 1st, increasing to 3.7° on the 24th after which Iris starts moving back towards Hamal.

(89) JULIA is in Pegasus all month. It is at opposition at the beginning of September. For a few nights it will reach magnitude 9.0. On the 2nd it will form a near equilateral triangle with the stars zeta Peg (mag 3.4) and xi Peg (mag 4.2). Julia´s motion will take it past zeta, the two being 8 arc-minutes apart on the 8th. By the end of September Julia will have faded to magnitude 9.4.

Near Earth Object (3122) FLORENCE rapidly fades in early September as its distance from the Earth increases. On the 1st it will be at mag 8.9, 7 million km from the Earth and moving at about 24 arc-minutes per hour. The next two nights finds it in Delphinus, magnitudes 9.1 and 9.3 respectively. It is in Vulpecula at magnitude 9.6 on the 4th and in Cygnus at 9.9 on the 5th. By then Florence will be 8.4 million km away with an apparent speed 17 arc minutes per hour. [See below for a daily ephemeris for Florence.]

-- Brian Loader

4. (3122) Florence Fly-By

Asteroid (3122) Florence passes 0.047 AU, 7 million km, from Earth on September 1. At that time it will be moving across the sky at 24'/hour, a full-moon diameter in 80 minutes. In a telescope it will appear as a ninth magnitude star.

A daily ephemeris is below. To get ephemerides for other times go to the Minor Planet Center's website at http://www.minorplanetcenter.net/iau/MPEph/MPEph.html Enter 3122 in the Object window. The format for the ephemeris start time is YYYY MM DD HHMM in UT. Observatory Code 485 (Carter Observatory) is close enough for all New Zealand.

(3122) Florence Positions at 12h UT = midnight NZST in August-September.

      R.A.(2000)Dec.                 R.A.(2000)Dec.
Date h  m  s    °  '  Mag.     Date h  m  s    °  '  Mag.
16  23 00 00  -61 27  11.7     26  21 52 45  -40 31   9.6
17  22 54 54  -60 32  11.5     27  21 44 14  -35 40   9.4
18  22 49 26  -59 29  11.4     28  21 35 29  -29 54   9.1
19  22 43 35  -58 15  11.2     29  21 26 31  -23 07   8.8
20  22 37 23  -56 49  11.0     30  21 17 23  -15 19   8.7
21  22 30 48  -55 07  10.8     31  21 08 07  -06 42   8.7
22  22 23 52  -53 08  10.6      1  20 58 46  +02 25   8.8
23  22 16 34  -50 45  10.4      2  20 49 21  +11 31   9.0
24  22 08 57  -47 56  10.2      3  20 39 55  +20 07   9.3
25  22 01 00  -44 34   9.9      4  20 30 31  +27 52   9.6

5. Safe Solar Eclipse Viewing

On August 21, US date, a total solar eclipse track crosses the United States. Nothing will be seen from New Zealand. However, the American Astronomical Society (AAS) has put out a warning about eclipse viewers that might be a useful reference for anyone wanting to look at the sun by eye or planning to view a solar eclipse.

On August 21, US date, a total solar eclipse track crosses the United States. The partial eclipse phase will be seen from all North America and the northern part of South America. Nothing will be seen from New Zealand.

The AAS's page on safe eclipse viewing is at https://eclipse.aas.org/eye-safety

The AAS's Reputable Vendors of Solar Filters & Viewers page is at https://eclipse.aas.org/resources/solar-filters

An article on Sky & Telescope's webpage warns of unsafe eclipse viewers that are being hawked around. Some paragraphs from it:

How can you tell if your "eclipse glasses" or handheld solar viewers are safe? It is no longer sufficient to look for the logo of the International Organization for Standardization (ISO) and a label indicating that the product meets the ISO 12312-2 international safety standard for filters for direct viewing of the Sun´s bright face. Why not? Because it now appears that some companies are printing the ISO logo and certification label on fake eclipse glasses and handheld solar viewers made with materials that do not block enough of the Sun´s ultraviolet, visible, and infrared radiation to make them truly safe. Some sellers are even displaying fake test results on their websites to support their bogus claim of compliance with the ISO safety standard.

Given this unfortunate situation, the only way you can be sure your solar viewer is safe is to verify that it comes from a reputable manufacturer or one of their authorized dealers. The AAS Solar Eclipse Task Force has been working diligently to compile a list of such vendors, now posted on its Reputable Vendors of Solar Filters & Viewers page. See the link above.

How can you tell if your solar viewer is NOT safe? The only thing you can see through a safe solar filter from a reputable vendor is the Sun itself. If you can see ordinary household lights through your eclipse glasses or handheld viewer, it´s no good. Safe solar filters produce a view of the Sun that is comfortably bright (like the full Moon), in focus, and surrounded by black sky. If you glance at the Sun through your solar filter and find it uncomfortably bright, out of focus, and surrounded by a murky haze, it´s no good.

Some eclipse glasses and solar viewers are printed with warnings stating that you shouldn´t look through them for more than 3 minutes at a time and that you should discard them if they are more than 3 years old. Such warnings are outdated and do not apply to eclipse viewers compliant with the ISO 12312-2 international safety standard, which was adopted in 2015. If your eclipse glasses or viewers are relatively new and are ISO 12312-2 compliant, you May look at the uneclipsed or partially eclipsed Sun through them for as long as you wish. Furthermore, if the filters aren´t scratched, punctured, or torn, you May reuse them indefinitely.

What about welding filters? The only ones that are safe for direct viewing of the Sun with your eyes are those of Shade 12, 13, or 14. These are much darker than the filters used for most kinds of welding. If you have an old welder´s helmet and are thinking of using it to view the Sun, make sure you know the filter´s shade number. If it´s less than 12 (and it probably is), don´t even think about using it to look at the Sun. Many people find the Sun too bright even in a Shade 12 filter, and some find the Sun too dim in a Shade 14 filter -- but Shade 13 filters are uncommon and can be hard to find. The AAS´s Reputable Vendors of Solar Filters & Viewers page doesn´t list any suppliers of welder´s filters, only suppliers of special-purpose filters made for viewing the Sun.

For much more see http://www.skyandtelescope.com/astronomy-news/aas-offers-updated-advice-for-safely-viewing-the-August-21st-solar-eclipse-across-america/AAS´s Advice for Safe Solar-Eclipse Viewing

6. Auckland Astronomical Society on YouTube

The Auckland Astronomical Society is now broadcasting many of its meetings and speakers online through its YouTube channel. You can choose to watch the events live or at a later time, perfect if you cannot make a meeting or would like to see the talk again.

You can subscribe to the YouTube channel at: https://www.youtube.com/channel/UC4W5_RJtWZBceOteC-8PTIA

-- Note from Simon Lowther.

7. Variable Star News

The Variable Stars South Newsletter 2017-3 (July) is now available for download from the website https://www.variablestarssouth.org/ Items of interest:

New Director of VSS Stan Walker has announced that he is retiring as Director of the RASNZ Section Variable Stars South. The new Director is Mark Blackford who has been a pioneer of making DSLR imaging quantitative; he is well known for his papers and manuals on DSLR photometry. Mark contributed to the RASNZ Whakatane Conference and associated Variable Star Symposium in 2014 and also attended the Tekapo Conference. Stan´s comments on signing off and some of Mark´s thoughts on directions for VSS are given in the July issue of the VSS Newsletter. See it in the VSS July Newsletter.

Large Telescope Installed Stephen Hovell has an observatory, Pukemanu, 11 km south-east of Kaitaia. For his new observatory he planned to have a Dobsonian with a 24" mirror but has ended up with a 28" f/3.3 scope. The mirror was manufactured by Lockwood Custom Optics in USA and the telescope constructed and installed by SDM (stands for Size does matter) run by Peter Read who is located in Bunbartha, Victoria, Australia. The telescope arrived in March and is now safely installed. For a full description of the components of the system see the article in the July VSS Newsletter.

Stephen is a dedicated visual observer and is pleased with the reach of his new telescope with which on most nights he can observe down to magnitude 16.5 or 17.0, allowing him to follow R Coronae Borealis and other variables further through their deep minima light curves.

Stars Types Featured in July Issue Mati Morel´s investigation of the identity of 142 variable stars in the Innes catalogue developed in 1914, 1915 & 1917. Stan Walker has an article on the humps of R Tel and another on extending the Double Maxima Mira project to other, moderate mass, pulsating variables. It includes a description of methods of observing and reporting. Tom Richards describes the O-C (observed -calculated) method for calculating changes in the period of eclipsing binaries which are used in astrophysical studies of these stars and invites observers to contribute to this programme.

-- Alan Baldwin

8. Asteroid Moon Discovered By Amateur Astronomers

A team of amateur observers, some using just 75 mm telescopes, have found that the main-belt asteroid (113) Amalthea probably has a small companion.

Each year, amateur astronomers get worldwide predictions for hundreds of events during which a distant asteroid briefly occults (hides) a star. But some of these occultations - like the one involving asteroid 113 Amalthea last March 14th - are anticipated more eagerly than others.

That date has been circled on Paul Maley's calendar for about 8 months. A retired NASA staffer and a key member of the International Occultation Timing Association, last year Maley started enlisting amateur observers in Texas to observe the occultation of a 10th-magnitude star by 13th-magnitude Amalthea. And all that planning paid off, because the observing team has discovered that this asteroid probably has a small satellite.

It's a robust "probably." As detailed in the IAU's Electronic Telegram 4413, issued on July 12th, a "fence" of 10 observing sites spread across the occultation's predicted path yielded seven positive occultations and three "misses." One of those misses, by Sam Insana in Gila Bend, Arizona, fell between five positive occultation tracks to his north and two to his south.

In other words, Insana was fortuitously positioned in the gap between Amalthea and its moon. Two short breaks were recorded by Dave Eisfeldt and Dick Campbell (Central Texas Astronomical Society) which corresponded to interruptions of the star's light by the moon. "This is the first time that two chords have been observed across a previously unknown minor-planet satellite," comments Daniel W. E. Green in the announcement. There were five other members of the team, one of whom set up four robotic cameras for the event.

Not to be confused with Jupiter's small satellite of the same name, Amalthea orbits the Sun every 3.66 years in a reasonably circular orbit that averages 2.37 astronomical units (324 million km) from the Sun with an inclination of 5°. Discovered in 1871, it's about 46 km across and has a rocky "S type" surface spectrum, which is typical for the bodies that populate the inner main belt. Based on the lengths of each occultation record and how they line up in the plot, Amalthea must have a distinctly elongated shape.

The size of the satellite isn't known, though typically such companions are much smaller than their hosts. According to the definitive compilation by Wm. Robert Johnston, the census of asteroids with moons now includes 133 main-belt asteroids (8 with two each), 22 Mars crossing asteroids (1 with two), and 62 near-Earth asteroids (2 with two each). Looking farther outward, Johnston's listing includes 4 of Jupiter's Trojans and 81 trans-Neptunian objects.

Confirmation of the discovery might not have to wait long. Although no one had previously observed a stellar occultation by Amalthea, four are predicted for next year - including an April 14th event with a track that crosses the north-central U.S.

-- From an article by Kelly Beatty on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/amateur-observers-discover-asteroid-moon/

9. Cassini's Last Looks at Saturn

The ringed planet seems to be hanging on to at least some of its secrets right up until the very end.

The NASA-ESA-ASI robotic spacecraft Cassini is now in the midst of a series of dramatic weekly Grand Finale dives through the gap between Saturn and its ring system. This follows a series of wider Ring Grazing Orbits spanning late 2016 into earlier this year, and will climax with the end of the mission itself in September.

Cassini is now in the 16th of a total of 22 weekly orbits, coming as close as 3000 km to the planet's cloud tops. This allows the mission to not only examine the magnetic field of the planet close up, but also allows Cassini a chance to sample the upper atmosphere of the planet itself.

These final orbits are a bit of a risk, as the spacecraft must thread its way through the ring plane at 124,000 kph (34 km/s). This elevated risk is one reason that researchers have held off on the exploration of Saturn close-up until now.

One of the strangest recent findings from Cassini is what it didn't find: much of a discernible difference in tilt between Saturn's rotational axis and its magnetic field. In other planets, this tilt sustains the dynamos that emanate from liquid metal cores. Think of Earth, where liquid iron in its outer core generates our protective magnetic field - and a magnetic pole offset from Earth's true, rotational pole.

Cassini's magnetometer has found that Saturn's magnetic pole - in this case, generated by liquid metallic hydrogen in its core - is remarkably well aligned with the planet's rotational axis, down to less than 0.06 degrees. This finding flies in the face of how we think planetary magnetic fields are generated, suggesting that we don't understand Saturn's internal structure as well as we thought we did.

The surprisingly good alignment also masks the true length of Saturn's day. While we see the planet's cloud tops spinning once every 10 hours, 14 minutes near the planet's equator, a gaseous planet doesn't all rotate at the same rate so its rotation changes at the poles. A discernible tilt in the magnetic field would make the field wobble, betraying the core's true rotational speed. Since scientists haven't been able to measure the wobble, the length of Saturn's day remains a mystery.

On the first plunge through the ring plane, Cassini went "dish first," using its large radio antenna to protect the bulk of the spacecraft while a few instruments made tentative peeks out around the edges to "sniff" the local environment. But as researchers discovered the gap between the planet and the rings is - at least where Cassini sampled it - surprisingly devoid of debris, engineers relaxed constraints somewhat on subsequent passages, bringing other instruments to bear. Cassini has since used its Ion and Neutral Mass Spectrometer (INMS) to sample the tenuous exosphere of Saturn's atmosphere and its Cosmic Dust Analyser (CDA) to sample the few ring particles obtained on each pass.

What's next? Cassini will dive deeper still on final passes and the INMS is expected to get better atmospheric samples on each pass. And of course, we've getting some thrilling up close images of Saturn itself, with more to come.

Launched two decades ago in 1997, the Cassini mission promises a thrill ride to the very last moment, just over one month away. Cassini is on a ballistic date with destiny, meaning that even if the spacecraft were to fall silent, destruction via atmospheric entry on September 15th is assured. But the science results will continue to pay off for years to come. Not bad for a spacecraft launched last century.

-- From an article, dated July 31, by David Dickinson on Sky & Telescope's website at http://www.skyandtelescope.com/astronomy-news/saturn-surprises-cassini-right-up-until-the-end/

10. Brown Dwarfs Common?

A new study of a nearby cluster of newly formed stars reveals that brown dwarfs might rival stars in the Milky Way in number, with one brown dwarf for every two bona fide stars.

Since their discovery in 1995, brown dwarfs, so-called "failed stars", have fascinated astronomers. At less than 8% the mass of the Sun, brown dwarfs fail to ignite fusion in their core. Glowing initially with the heat of their formation, they slowly cool over billions of years like dim red embers. Due to their intrinsic faintness, most of the known brown dwarfs are relatively close to the Sun, within a few thousand light years. But there are brown dwarfs beyond the grasps of our telescopes - we just don´t know exactly how many.

Now, an international team of astronomers, led by Koraljka Muzíc (University of Diego Portales, Chile, and University of Lisbon, Portugal), has estimated that the Milky Way contains many more brown dwarfs than we once thought. The article is available on the astrophysics arXiv.

Muzíc and collaborators trained the European Southern Observatory's Very Large Telescope (VLT) on the RCW 38 star-forming cluster 5,500 light-years from the Sun. Most of the Milky Way´s stars began in similar clusters over billions of years. Such clusters are still valued for studying how stars form and how environment - the physical properties of the gas and dust in the natal cloud - can influence the distribution of the stars that form in the cluster. Even small cluster-to-cluster variations can have a big impact on the final stellar population of the Galaxy.

RCW 38 is massive, as star clusters go, and vigorously forming new stars. Muzíc's team imaged deep into the cluster, identifying bright massive stars and dim brown dwarfs within the same data. Using the VLT, the team was able to capture brown dwarfs with masses down to about 2% that of the Sun.

The team found more brown dwarfs than expected from previous cluster studies. That suggests that brown dwarfs May be more common than previously thought. In this cluster, there´s approximately one brown dwarf for every two bona fide stars. When applied to the rest of the galaxy (which contains some 200 billion stars), that adds up to about 100 billion brown dwarfs, dimly gliding along in the Milky Way.

This result will be directly tested on two fronts. First, studies will continue to refine the brown dwarf populations within other star clusters, such as the Orion Nebula Cluster. Next, large upcoming surveys such as WFIRST and LSST will image the galactic field to faint brightnesses, enabling astronomers to extend the local brown dwarf census. These faint almost-stars May prove to be just as ubiquitous as their stellar siblings.

-- From an article by John Bochanski on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/100-billion-brown-dwarfs-milky-way/

11. Life-Building Chemical Found Around Young Stars

ALMA has observed stars like the Sun at a very early stage in their formation and found traces of methyl isocyanate - a chemical building block of life. This is the first ever detection of this prebiotic molecule towards solar-type protostars, the sort from which our Solar System evolved. The discovery could help astronomers understand how life arose on Earth.

Two teams of astronomers used the Atacama Large Millimeter/ submillimeter Array (ALMA) in Chile to detect the prebiotic complex organic molecule methyl isocyanate in the multiple star system IRAS 16293-2422. A complex organic molecule is defined in astro-chemistry as consisting of six or more atoms, where at least one of the atoms is carbon. Methyl isocyanate contains carbon, hydrogen, nitrogen and oxygen atoms in the chemical configuration CH3NCO. This family of organic molecules is involved in the synthesis of peptides and amino acids, which, in the form of proteins, are the biological basis for life as we know it.

IRAS 16293-2422 was previously studied by ALMA in 2012 and found to contain molecules of the simple sugar glycolaldehyde, another ingredient for life.

ALMA´s capabilities allowed both teams to observe the molecule at several different and characteristic wavelengths across the radio spectrum. They found the unique chemical fingerprints located in the warm, dense inner regions of the cocoon of dust and gas surrounding young stars in their earliest stages of evolution. Each team identified and isolated the signatures of methyl isocyanate. They then followed this up with computer chemical modelling and laboratory experiments to refine our understanding of the molecule´s origin.

IRAS 16293-2422 is a multiple system of very young stars, around 400 light-years away in a large star-forming region called Rho Ophiuchi in the constellation of Ophiuchus (The Serpent Bearer). The new results from ALMA show that methyl isocyanate gas surrounds each of these young stars.

Earth and the other planets in our Solar System formed from the material left over after the formation of the Sun. Studying solar-type protostars can therefore open a window to the past for astronomers and allow them to observe conditions similar to those that led to the formation of our Solar System over 4.5 billion years ago.

The detection supports laboratory results that show that methyl isocyanate can be produced on icy particles under very cold conditions that are similar to those in interstellar space This implies that this molecule - and thus the basis for peptide bonds - is indeed likely to be present near most new young solar-type stars.

-- From European Southern Observatory press release eso1718 forwarded by Karen Pollard. See the original with images and links at https://www.eso.org/public/unitedkingdom/news/eso1718/

12. Mt John History Price Reduced

The Mt John history 'Mt John - The First 50 Years', a celebration of half a century of optical astronomy at the University of Canterbury by John Hearnshaw and Alan Gilmore, published in March 2015 is now selling for $20. It was $60. For details see http://www.cup.canterbury.ac.nz/catalogue/mt_john.shtml

13. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2017 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

14. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

For an application form contact the Executive Secretary This email address is being protected from spambots. You need JavaScript enabled to view it., Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

15. Quotes

"The most dangerous person is the one who listens, thinks and observes." -- Bruce Lee.

"Meetings are indispensable when you don't want to do anything." -- J.K. Galbraith.

"What I write is smarter than I am - because I can rewrite it." -- Susan Sontag.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
P.O. Box 57 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand

RASNZ Electronic Newsletter July 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 199

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Third International Starlight Festival, 13-15 October
2. Harry Williams Astrophotography Competition
3. The Solar System in July
4. Solar Probe
5. Xenon Calibrates Comets' Relation to Earth
6. Orbiting Pair of Supermassive Black Holes
7. Gravitationally-lensed Supernova Found
8. Fast Radio Burst FRB 121102 (cont.)
9. How to Join the RASNZ
10. Gifford-Eiby Lecture Fund
11. Kingdon-Tomlinson Fund
12. Quotes

1. Third International Starlight Festival, 13-15 October

The Third International Starlight Festival will be held at the Hermitage, Mt Cook over three days in 2017, 13-15 October.

The Festival will celebrate the Aoraki Mackenzie International Dark Sky Reserve (www.darkskyreserve.org.nz) whose mission is to encourage and protect dark skies free of light pollution in the Mackenzie, and to promote star gazing and astro-tourism. We do this by organizing a Starlight Festival every second year for the benefit of the public and international tourists. Astro-tourism in the Mackenzie at Tekapo and Mt Cook is now one of New Zealand?s biggest tourist attractions, with about 200,000 people coming to Tekapo annually, many from Asia and Europe, to see the stars.

The 2017 Festival will be our third, after very successful events in 2013 in Tekapo and 2015 at Twizel. The Festival will be a mixture of events including lectures, workshops, exhibitions, videos and documentaries, planetarium shows and of course, star-gazing. We have engaged three world-class speakers to come to Mt Cook for the Festival. They are:

  • Dr Natalie Batalha NASA Ames space scientist, Moffett Field (near San Francisco), California. (Time Magazine in April 2017 named her as one of the 100 most influential people on the planet). She will talk about ?A Planet for Goldilocks? and the search for habitable Earth-like planets
  • Kevin Govender, Director of the Office of Astronomy for Development of the International Astronomical Union, based in Cape Town, South Africa. He will talk about ?Astronomy for Humankind?.
  • Sze-leung Cheung, Director of the Office of Astronomy Outreach of the International Astronomical Union, based in Tokyo, Japan. He will talk about ?The threat of LEDs to astronomy and how to build a dark-sky-friendly future?.

All three are outstanding speakers, and Sze-leung Cheung is fluent in Chinese as well as English, so can give his talk in both languages to attract overseas tourists.

More details on the Third Starlight Festival and our keynote speakers are at www.starlightfestival.org.nz. On-line ticket sales will be available from mid-July. The website also has all accommodation options in and near Mt Cook.

Mark Gee from Wellington will show some of his stunning night-sky time-lapse animations and on the morning of Oct 14 will conduct an astro-photography workshop for everyone wanting to learn these techniques. Steve Chadwick from Palmerston North will show his amazing night sky animations and photography, as will also the renowned Fairlie and Tekapo astrophotographer, Fraser Gunn.

There is also an astro-photography exhibition with nine of New Zealand?s top astro-photographers exhibiting their images. The Festival features videos, exhibitions, workshops, planetarium shows and stargazing (at the new Mt Cook Observatory) over three days, 13-15 October.

-- John Hearnshaw, Chair, Aoraki Mackenzie International Dark Sky Reserve Board.

2. Harry Williams Astrophotography Competition

Calling all Astrophotographers, the 2017 Harry Williams Astrophotography Competition is now open for entries, this year our judge is world-renowned planetary photographer Damian Peach, in 2010, Damian became the only Briton to win the prestigious Astronomy Photographer of the Year Award for his composite photograph of Jupiter's moons, Ganymede and Io, orbiting the stormy surface of the Gas Giant.

Astronz has generously offered to sponsor the Deep Sky category with a Astronz $300 gift voucher as well as providing an Astronz beanie for the winner of each category!

Not only will the overall winner of the competition receive the coveted Harry Williams Astrophotography Trophy to adorn his or her mantelpiece for a year but they will also receive an OPTOLONG L-Pro light pollution filter worth $269 US dollars thanks to the very generous sponsorship of OPTOLONG Astronomical Filters.

As in previous years we are lucky to have Australian Sky & Telescope on board as sponsors of both the Solar System category and the Miscellaneous /Artistic category, the winners of these categories will receive a one year subscription to the magazine as well as the usual cash prize.

Also the winner of the Newcomers contest will receive a signed copy of 'Imaging the Southern Sky' by Steve Chadwick & Ian Cooper, more sponsors to be announced soon.

The competition cut-off date is August 31 and the competition awards will be announced at the annual Burbidge Dinner which is the Auckland Astronomical Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.

The competition rules and entry forms can be found on the Auckland Astronomical Society website http://www.astronomy.org.nz/new/public/default.aspx

-- From Jonathan Green's posting to the nzastronomers Yahoo group.

3. The Solar System in August

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.

Sunrise, Sunset and Twilight Times in May

Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

                 August  1  NZST                August 31  NZST
       SUN: rise: 7.26am,  set: 5.28pm    rise:  6.45am,  set: 5.57pm
Twilights     morning       evening          morning       evening
Civil:    starts: 6.59am, ends: 5.55pm   starts: 6.20am, ends: 6.23pm
Nautical: starts: 6.26am, ends: 6.39pm   starts: 5.48am, ends: 6.55pm
Astro:    starts: 5.54am, ends: 7.01pm   starts: 5.16am, ends: 7.27pm

August Phases of the Moon (times NZST, as shown by GUIDE)

  Full moon:     August  8 at  6.11 am (Aug  7, 18:11 UT)
  Last quarter   August 15 at  1.15 pm (01:15 UT)
  New moon:      August 22 at  6.30 am (Aug 22, 18:30 UT)
  First quarter: August 29 at 12.13 pm (00:13 UT)

The Planets in August 2017

Mercury is visible in the early evening sky during the first part of August while Jupiter remains visible until later evening. Saturn is there all evening. In the morning Venus is bright before sunrise. Mars is not visible during the month.

MERCURY starts August as a prominent early evening object, magnitude 0.4 setting well over two hours after the Sun. The planet begins the month in Leo some 6.5° above Regulus. During August it loops into Sextans but its elongation from the Sun rapidly declines and as it does the planet loses brightness. On the 27th Mercury is at inferior conjunction between the Earth and Sun.

VENUS continues as an easily seen morning object although by the end of the month it rises less than 90 minutes before the Sun. During August it crosses Gemini and moves into Cancer on the 24th. On the morning of August 20 it will be joined by the crescent moon, some 8° to the right of the planet.

MARS remains too close to the Sun to observe during August, rising at best only 23 minutes before the Sun on the 31st.

JUPITER remains easily visible in the early evening sky, although by the end of August it will set mid evening. The planet is in Virgo below Regulus, their separation slowly decreasing. By the end of the month the two will be less than 4° apart. On the 25th the crescent moon will join them be some 6° below Jupiter.

SATURN is still well placed in the evening sky during August, not setting until after midnight. The planet is in Ophiuchus, its position changing very little during the month. It is stationary on the 25th. The moon will be less than 4° from Saturn on the 3rd of August. The two are close again on the 30th, this time 5° apart mid evening.

Outer Planets URANUS rises close to midnight at the beginning of August and two hours earlier by the end of the month. The planet remains in Pisces at magnitude 5.8. It is stationary on the 3rd.

NEPTUNE rises at 8.15 pm on August 1 advancing to a few minutes after sunset on the 31st. It is in Aquarius at magnitude 7.8.

PLUTO, magnitude 14.4, remains in Sagittarius. It will be less than a degree from the magnitude 2.9 star, pi Sgr, by the end of the month.

Minor Planets (1) CERES is in the morning sky, rising about 4.00 am by the end of August. It is in Gemini ending the month just over 5° from Pollux; magnitude 8.9.

(2) PALLAS is a morning object in Eridanus brightening from magnitude 9.5 to 9.0 during August.

(4) VESTA is an 8th magnitude object in Leo during August. At the beginning of the month it will be some 6° to the right of Mercury in the early evening. By the end of August, Vesta will be setting an hour after the Sun.

(7) IRIS is a morning object brightening from magnitude 9.2 to 8.6 during the month. Although starting August in Pisces it soon moves into Aries where it is 1° from Beta Ari, mag 2.6 on the 13th and less than 2° from Alpha Ari at the end of the month.

(3122) Florence has a diameter of a few kilometres. Discovered in 1981 it is listed as a potential threat to Earth. It will be some 7 million kilometres from the Earth at the end of August with magnitude 8.8. By then it should have an apparent motion over 20 arc-minutes per hour. Its path will see it pass some 16° from Fomalhaut on August 27 and less than 15° from Altair on September 2.

4. Solar Probe

NASA's Parker Solar Probe, set to launch in 2018, will be humanity's first effort to "touch the Sun," revolutionizing our understanding of the Sun's corona, the solar wind, and the greater heliosphere. Parker Solar Probe

NASA has announced that they are retitling the Solar Probe Plus, humanity's first mission to the outer layers of the Sun, the Parker Solar Probe. The new name honours astrophysicist Eugene Parker, whose years' of work in the field known as "space weather" have helped us understand the interactions between stars and their orbiting bodies.

In the latter half of the 1950s, a young professor teaching astronomy and physics at the University of Chicago's Enrico Fermi Institute, Eugene Parker, published an article in the Astrophysical Journal entitled "Dynamics of the interplanetary gas and magnetic fields." The paper introduced the idea of a wind emanating from the Sun, a concept so controversial that two reviewers rejected the paper. In the end, it was only published because Subrahmanyan Chandrasekhar, the journal's science editor at the time (and no stranger himself to rejection for revolutionary thinking), overruled the reviewers' decisions.

Much of Parker's work at the time focused on the Sun's radiation and its potential effects on the planets. In his 1958 paper, Parker hypothesized that there was a constant stream of high-energy particles and radiation escaping from the surface of the Sun, an idea that ran contrary to the accepted view of the time that this space contained only a vacuum. But it was controversial only for a little while ? in 1962 Mariner 2 confirmed the existence of the solar wind.

While observations proved the solar wind existed, they weren't able to fully answer how or why the Sun's tenuous outer atmosphere, or corona, should sear at a temperature of millions of degrees. The Sun's visible surface, after all, is only several thousand degrees, so something must be heating the matter farther from the Sun, but scientists have long debated what that process could be. The Parker Solar Probe will address that fundamental question, completing seven flybys of Venus between 2018 and 2024 to slowly spiral into orbits that take it within 3.9 million miles (9 solar radii) of the Sun.

At its closest approach, the spacecraft will hurtle around the Sun at 200 km/s at a distance nearly ten times closer to the Sun than Mercury (on average), and seven times closer than any spacecraft has ever come before. The probe will perform its scientific investigations in a region of intense heat and radiation, and its instruments must thereby be protected by a 4.5-inch thick carbon-composite heat shield, able to withstand temperatures of up to 1400°C.

The mission's main goal is to trace heat and energy flow through the corona and explore what causes charged particles to accelerate away from the surface of the Sun. To that end, the instrument aboard the Parker Solar probe will study every aspect of the Sun from its magnetic and electric fields to the solar wind.

  • The FIELDS instrument consists of five voltage sensors as well as three magnetometers, sensors which measure magnetic field. It will make detailed measurements of the corona's electric and magnetic fields, as well as other gauging electron temperature and plasma density.
  • The ISIS instrument will observe solar energetic particles (SEPs) such as electrons, protons, and heavy ions accelerated to energies as high as 100 MeV, correlating these particles with larger coronal structures and the solar wind.
  • WISPR, a wide field telescope imager, will supplement the raw data captured by the FIELDS and ISIS instruments with high-quality photographs.
  • SPAN-A+ and SPAN-B will measure the velocity, temperature, and density distributions of the electrons, protons, and helium ions.

Together, these instruments will help unlock the answers to the Sun's most puzzling questions ? all the while helping to protect a society that is becoming increasingly dependent on satellites and other technology vulnerable to the threats of space weather.

-- From an article by Chris Stubenrauch on Sky & Telescope's website at http://www.skyandtelescope.com/astronomy-news/nasa-parker-solar-probe-touch-sun/

---------- In the late 1920s the English mathematical physicist E A Milne also suggested the existence of a solar wind. See 'Beating the Odds: The Life and Times of E A Milne' by Meg Weston Smith. -- Ed.

5. Xenon Calibrates Comets' Relation to Earth

Xenon measured by the European Space Agency's Rosetta spacecraft has shed light on a long-standing mystery about the role comets played in Earth's formation.

A noble gas is serving as a key tracer for sleuthing out early solar system formation. Researchers led by Bernard Marty (CNRS, France) announced June 9th in Science that the chemical signature of the gas xenon ? an element that exists in minute quantities in Earth's atmosphere ? was also detected in the tenuous envelope surrounding Comet 67P/Churyumov-Gerasimenko in the final months of the European Space Agency's Rosetta mission.

Xenon is a noble gas, element number 54 on the periodic table. Because it doesn't react with other elements, it serves a crucial role in tracing the source of proto-solar material that ultimately created Earth and other planets. This gas has 10 different isotopes, each containing a different number of neutrons. The lightest isotopes of xenon are created during supernova explosions; its medium-weight isotopes form when low- to medium- mass stars enter the asymptotic giant phase of their lives; and the very heaviest occur during energetic neutron star mergers.

?Xenon is the heaviest stable noble gas and perhaps the most important because of its many isotopes that originate in different stellar processes,? says Marty in a recent press release. ?Each one provides an additional piece of information about our cosmic origins.?

By accounting for this measured loss, scientists soon realized that the levels of heavy isotopes in Earth's primordial xenon mix (referred to as ?U-xenon?) were lower than that found in xenon's ratios elsewhere in the solar system, such as in the solar wind and asteroids. Such a discrepancy has become known as the ?xenon paradox.?

Comets have unique compositions because they formed very far from the Sun. For example, their ratios of deuterium to hydrogen are consistently higher than anywhere else in the solar system. Should xenon show similar discrepancies?

To get the key samples from Comet 67P, Rosetta had to get within just 5 to 8 km of the nucleus. This was a challenging manoeuvre for the mission's navigation team, as dust sublimating off the comet can confuse the spacecraft's star trackers. ESA controllers decided to perform the critical manoeuvre in the last half of May 2016.

The spacecraft used a mass spectrometer in its ROSINA instrument suite to measure xenon isotope levels over a span of three weeks. This extended study identified seven isotopes of xenon, with a relatively abundant blend of light isotopes relative to heavy ones. This ratio is markedly different from that seen in asteroids and the solar wind today ? but similar to the predicted U-xenon ratio of primordial Earth. Marty and his team conclude that comets contributed 22% to the mix of xenon sources delivered to Earth.

This is also the first time that scientists were able to establish a definitive link between comets ? thought to represent pristine examples of the early solar system ? and the atmospheric composition of Earth. Comets delivering xenon to the early Earth likely contributed prebiotic material such as the amino acid glycine and phosphorus, also detected by Rosetta on Comet 67P.

But Earth's water lacks the high deuterium to hydrogen ratio seen in Comet 67P, so comets must have played a limited role in delivering water to the Earth. A more likely source for that, geochemists now suspect, was the population of water-rich carbonaceous chondrite asteroids.

?This conclusion is in accord with previous measurements performed by Rosetta,? says Kathrin Altwegg (University of Bern, Switzerland) in a recent press release, ?including the unexpected detections of molecular oxygen and di-sulphur, and the high deuterium-to-oxygen ratio observed in the comet water.?

Earth is unique in the solar system as the only world which wears its extensive oceans of liquid water on the outside ? every other world inside the ?frost line? of the inner solar system is bone dry.

Standard models of solar system formation predict an early creation of the outer gas giant worlds, with untold numbers of comets lingering farther out in the Kuiper Belt and trillions more flung to the distant realm of the Oort Cloud by gravitational encounters with the outer planets. Now, we're seeing just how comets May have contributed to the present composition of the inner rocky worlds as well.

Samples from Comet 81P/Wild returned by NASA's Stardust mission suggest that elements originating from the interior of the early solar nebula ? particularly isotopes of oxygen ? were transported outward through the early solar system.

No future comet sample return mission is in the works, though the bonanza of science returned by Rosetta certainly shows that another Stardust follow up is due.

When it comes to unravelling the riddle of early solar system formation, the new mantra for the future might be to ?follow the xenon.?

From an illustrated article by David Dickinson on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-blogs/astronomy-space-david-dickinson/rosetta-finds-clues-to-xenon-paradox/

6. Orbiting Pair of Supermassive Black Holes

Using the super-sharp radio 'vision' of the National Science Foundation's Very Long Baseline Array (VLBA), astronomers have made the first detection of orbital motion in a pair of supermassive black holes in a galaxy some 750 million light-years from Earth.

The two black holes, with a combined mass 15 billion times that of the Sun, are likely separated by only about 24 light-years, extremely close for such a system.

"This is the first pair of black holes to be seen as separate objects that are moving with respect to each other, and thus makes this the first black-hole 'visual binary'" said Greg Taylor, of the University of New Mexico (UNM).

Supermassive black holes, with millions or billions of times the mass of the Sun, reside at the cores of most galaxies. The presence of two such monsters at the centre of a single galaxy means that the galaxy merged with another sometime in the past. In such cases, the two black holes themselves May eventually merge in an event that would produce gravitational waves that ripple across the universe.

"We believe that the two supermassive black holes in this galaxy will merge," said Karishma Bansal, a graduate student at UNM, adding that the merger will come at least millions of years in the future.

The galaxy, an elliptical galaxy called 0402+379, after its location in the sky, was first observed in 1995. It was studied in 2003 and 2005 with the VLBA. Based on finding two cores in the galaxy, instead of one, Taylor and his collaborators concluded in 2006 that it contained a pair of supermassive black holes.

The latest research, which Taylor and his colleagues are reporting in the Astrophysical Journal, incorporates new VLBA observations from 2009 and 2015, along with re-analysis of the earlier VLBA data. This work revealed motion of the two cores, confirming that the two black holes are orbiting each other. The scientists' initial calculations indicate that they complete a single orbit in about 30,000 years.

"We need to continue observing this galaxy to improve our understanding of the orbit, and of the masses of the black holes," Taylor said. "This pair of black holes offers us our first chance to study how such systems interact," he added.

The astronomers also hope to discover other such systems. The galaxy mergers that bring two supermassive black holes close together are considered to be a common process in the universe, so astronomers expect that such binary pairs should be common.

"Now that we've been able to measure orbital motion in one such pair, We're encouraged to seek other, similar pairs. We May find others that are easier to study," Bansal said.

The VLBA, part of the Long Baseline Observatory, is a continent-wide radio telescope system using ten, 240-ton dish antennas distributed from Hawaii to St. Croix in the Caribbean. All ten antennas work together as a single telescope with the greatest resolving power available to astronomy. That extraordinary resolving power allows scientists to make extremely fine measurements of objects and motions in the sky, such as those done for the research on 0402+379.

-- From a press release from the Long Baseline Observatory in Socorro, New Mexico, forwarded by Karen Pollard.

7. Gravitationally-lensed Supernova Found

An international team of astronomers has, for the first time, seen a cosmic magnification of the light from a class of supernova called Type Ia. Type Ia supernovae -- often referred to as "standard candles" because of their well-known intrinsic brightness -- are frequently used by astronomers to accurately measure the expansion rate of our universe, as well as the amount of dark energy, which is thought to be accelerating this expansion.

Finding a magnified, or "gravitationally lensed," Type Ia supernova is like discovering a brighter candle with which to view the universe. The researchers say this discovery is the first of many to come, and that having a whole collection of similarly lensed Type Ia supernovas will lead to more precise measurements of our universe's most fundamental traits.

Gravitational lensing occurs when the gravity of a cosmic object, such as a galaxy, bends and magnifies the light of a more distant object. The effect can cause galaxies to appear strangely twisted, and even produce multiple images of the same object. While this phenomenon of gravitational lensing has been observed many times since the early 20th century, when it first was predicted by Albert Einstein, imaging a lensed Type Ia supernova has proven formidably difficult, until now.

In the new study, published April 21 in the journal Science, the researchers imaged the Type Ia supernova called iPTF16geu and found it duplicated into four different images.

"Resolving, for the first time, multiple images of a strongly lensed 'standard candle' supernova is a major breakthrough," says Ariel Goobar, a professor with the Oskar Klein Centre at the University of Stockholm, Sweden, and a lead author of the study. "Normally, when we view a lensed object, we don't know the intrinsic brightness of that object, but with a Type Ia supernova, we do. This will allow us to better quantify and understand the phenomenon of gravitational lensing."

Goobar and his group are partners in two Caltech-led international scientific collaborations -- the intermediate Palomar Transient Factory (iPTF) and the Global Relay of Observatories Watching Transients Happen (GROWTH) project. The iPTF takes advantage of the Palomar Observatory and its unique capabilities to scan the skies and discover, in near real-time, fast-changing cosmic events such as supernovas. GROWTH manages a global network of researchers and telescopes that can swiftly perform follow-up observations to study these transient events in detail.

Within two months of detection, the team observed the iPTF16geu supernova with the NASA/ESA Hubble Space Telescope; the adaptive-optics instruments on the W. M. Keck Observatory atop Maunakea, Hawaii; and the VLT telescopes in Chile. Apart from producing a striking visual effect, capturing the image of a strongly lensed Type Ia supernova such as iPTF16geu is extremely useful scientifically. Astronomers can measure very accurately how much time it takes for the light from each of the multiple images of the supernova to reach us. The difference in the time of arrival can then be used to estimate with a high precision the expansion rate of the universe, known as the Hubble Constant.

Another unique advantage of lensed Type Ia supernovas is that they can be identified with relatively small telescopes, such as the 48-inch Samuel Oschin Telescope at Palomar Observatory, which was used to image the iPTF16geu supernova. Larger telescopes are in high demand, and equipped with narrow-field cameras that take too much time to routinely scan the sky. The iPTF project scanned one-fifteenth of the visible sky every night. Its successor, the Zwicky Transient Facility (ZTF), set to begin observing this [northern] summer, will scan the skies even faster, and is capable of covering the entire accessible sky every night. By scanning large swaths of the sky, astronomers can sift through thousands of cosmic objects to find rare events such as the lensing of a Type Ia supernova.

While ZTF will be 10 times faster than iPTF, new facilities such as the Large Synoptic Survey Telescope (LSST) will be 10 times faster than ZTF. Clearly, the discovery of iPTF16geu suggests a wealth of new science that will be made possible with the LSST.

The study of iPTF16geu is already delivering interesting results. Using data from Keck and Hubble the team calculated that the lensing matter in the galaxy magnifying iPTF16geu has a mass up to 10 billion times that of the Sun and a radius of nearly 3,000 light-years. Compared to other lensing objects, this is relatively tiny. Studies of unusual lensed objects like this give astronomers a new peek into gravitational lensing and May redefine what we know about the factors, such as dark matter and Einstein's general theory of relativity, that contribute to lensing.

Reference: "iPTF16geu: A Multiply-Imaged Gravitationally Lensed Type Ia Supernova," A. Goobar et al., 2017 Apr. 21, Science [http://science.sciencemag.org].

-- From a Caltech press release forwarded by Karen Pollard.

8. Fast Radio Burst FRB 121102 (cont.)

Ground- and space-based observations have now shed intriguing new light on a mysterious radio source. (See Newsletter No. 194, 20 February 2017, Item 4.)

A puzzling source of ultra-brief radio bursts is slowly giving up some of its secrets. Three new papers, published on the arXiv preprint server in late May, have presented surprising new results on the only known repeating fast radio burst, dubbed FRB 121102. But despite the concerted efforts of some of the largest observatories, both on the ground and in space, the true nature of these enigmatic events remains a mystery.

Fast radio bursts are very brief explosions of radio waves, first discovered at the 64-meter Parkes radio telescope in Australia. Because of their unpredictability, their short duration (on the order of milliseconds), and the small field of view of a typical radio telescope, such bursts are hard to spot. But from the two dozen or so found so far, it follows that there must be thousands of these bursts occurring all over the sky every day.

Of these, FRB121102, first detected by the 305-meter Arecibo radio telescope in Puerto Rico, is special. After its discovery on 2012 November 2 (hence its name), it became the first of its kind to repeat, producing many additional bursts of radio waves. Whatever FRBs might be, they?re apparently not some one-off cataclysm.

In 2016 observations by the Very Large Array in New Mexico and the European VLBI Network succeeded in precisely pinpointing the sky location of the repeating radio source. It turned out to coincide with a remote, dim dwarf galaxy that also hosts a faint persistent source of radio waves. A paper published earlier this year already revealed that the FRB and the persistent radio source are separated by less than 12 milliarcseconds.

Ground- and space-based observations by a large international team of astronomers have now shed intriguing new light on this mysterious FRB. In February the dwarf galaxy ? 3.2 billion light-years away in southern Auriga ? was studied in detail by the Hubble Space Telescope, following earlier observations by the 8.1-meter Gemini-North telescope at Mauna Kea, Hawaii, and by NASA?s Spitzer Space Telescope. Meanwhile, a Japanese team also observed the puny galaxy with the 8.2-meter Subaru telescope, also at Mauna Kea.

The new observations reveal that the bursts originate in an active, compact star-forming region some 4,500 light-years across in the outskirts of the tiny galaxy. According to team member Jason Hessels (ASTRON, the Netherlands Institute for Radio Astronomy), this strongly suggests that the source of the bursts is a relatively young object ? probably a recently formed neutron star. ?FRB121102 might be considered a pulsar on steroids,? says Hessels. But it?s not yet clear whether the intermittent bursts are part of a regularly repeating signal, characteristic of pulsars.

The burst location has also been monitored by ESA?s XMM Newton observatory (in September 2016) and by NASA?s Chandra X-ray Observatory (in November 2016 and January 2017). But although Arecibo and the 110-meter Green Bank Telescope in West Virginia recorded a total of 12 new bursts during these periods (two of which were detected by both instruments), nothing was seen in X-rays. This indicates that the bursts? source is not just a scaled-up version of the young pulsar at the heart of the Crab Nebula. The Crab pulsar also emits giant radio flares (albeit half a million times less powerful than FRB121102!), but it?s a conspicuous X-ray source too.

Still, Hessels believes that the culprit must be a young stellar remnant ? maybe a rapidly spinning magnetar: a strongly magnetized neutron star. The faint persistent radio source could be the shock wave from the original supernova explosion, or a so-called pulsar wind nebula. Then again, known magnetars also produce powerful bursts of X-rays and gamma rays, which have not (yet) been observed in the case of FRB121102.

One of the other nagging questions is whether or not the repeating source is representative of all FRBs. No other fast radio bursts have been seen to repeat, despite various monitoring programs. Therefore, some researchers believe the repeater to be the odd one out. One of them is radio astronomer Duncan Lorimer of West Virginia University, who discovered the first FRB in Parkes data from 2001. ?I suspect there May be multiple classes,? he says.

-- From Govert Schilling's article at http://www.skyandtelescope.com/astronomy-news/homing-source-mysterious-fast-radio-burst/ Where references are listed.

9. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2017 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

10. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

For an application form contact the Executive Secretary This email address is being protected from spambots. You need JavaScript enabled to view it., Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

11. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants May be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 November 2016. Full details are set down in the RASNZ By-Laws, Section J. For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it. Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

12. Quotes

"We all know the Moon landing was staged. It was filmed by Stanley Kubrick. However, it cost an insane amount of money as Kubrick was a perfectionist and demanded they film on location." -- Liberty Memes.

"There is still no cure for the common birthday." -- John Glenn.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
P.O. Box 57 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand

RASNZ Electronic Newsletter June 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 198

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. John Hearnshaw MNZM
2. Norman Dickie 1916-2017
3. Horowhenua StellarFest, Foxton Beach, July 21-23
4. Harry Williams Astrophotography Competition
5. The Solar System in July
6. Potential Meteor Shower
7. First PhD prize Winners Announced by the IAU
8. Variable Star News
9. Setting up a Remote Observatory in Chile
10. LIGO's Third Gravity Wave Detection
11. Early Earth Life Might Help Locate Mars Life
12. Two New Moons for Jupiter
13. How to Join the RASNZ
14. Gifford-Eiby Lecture Fund
15. Kingdon-Tomlinson Fund
16. Quote

1. John Hearnshaw MNZM

The Queen's Birthday Honours list included Emeritus Professor John Bernard Hearnshaw as a Member of the New Zealand Order of Merit for services to astronomy. The citation reads:

Emeritus Professor John Hearnshaw was director of the Mt John Observatory of the University of Canterbury for a total of 25 years between 1976 and 2008, during which time he directed the construction of the McLellan telescope, the largest New Zealand-made telescope, as well as the construction of the HERCULES spectrograph.

Professor Hearnshaw pioneered the implementation of stellar spectroscopy in New Zealand, the method by which the chemical composition of stars is determined by analysing their spectra. He contributed to the establishment in 1994 of a collaboration between Japan and New Zealand named MOA to search for planets orbiting stars in the southern night sky. He is former Vice-President of the International Astronomical Union (IAU) Commission for Astronomy Education and Development, and of the IAU Division for Optical and Infrared Techniques. He is currently President of the IAU Division for Astronomy Education, Outreach and Heritage. He has been a long-time supporter of the Townsend Observatory for public astronomy in Christchurch. He facilitated the development of the New Zealand company KiwiStar Optics Ltd, which has supplied precision astronomical lenses and components for major telescopes in several countries. He was a founder of the Aoraki Mackenzie International Dark Sky Reserve and is currently Chairperson of the Reserve?s Board. Professor Hearnshaw has authored more than 200 publications on astronomy, including six books.

--- https://www.dpmc.govt.nz/honours/lists/qb2017-mnzm#hearnshawj

2. Norman Dickie 1916-2017

Norman Robert Dickie, the RASNZ's oldest member, died on June 4 at the age of 100. Thanks to the care of Gore Hospital and Norman's sons Ross and Grant, Norman had been able to attend the Saturday afternoon session of the RASNZ's Conference in Dunedin.

Norman was a co-discoverer of the bright Nova Puppis 1942, now CP Puppis, on 11 November 1942. Norman spotted it at 11pm while biking home from Home Guard duties. He contacted the Carter Observatory who confirmed that the nova had also been seen by Alex Crust in Wellington. Alex nominated Norman for RASNZ membership in 1945. Sadly the two never met as Alex died that year.

Norman and Ross travelled to Northland to see the total solar eclipse of 31 May 1965. Norman described it as a most beautiful and wonderful sight and the highlight of his life.

Norman's funeral in Gore on June 8 was attended by a wide range of people from the Gore community and a large contingent of astronomers. Ash Pennell spoke on behalf of the Dunedin Astronomical Society and Bob Evans on behalf the RASNZ. There was a similarly large attendance at Norman's 100th birthday last October.

3. Horowhenua StellarFest, Foxton Beach, July 21-23

The Horowhenua Astronomical Society is holding the sixth annual StellarFest in the Lower North Island on July 21-23 at the Foxton Beach Bible Camp, Foxton Beach, Horowhenua.

The overall theme of the weekend will be the Winter Milky Way. The venue is situated at a dark site so this wondrous area of the night sky will be easily visible and riding high in the sky.

The weekend will include: Hydrogen-alpha solar viewing and photography; interesting talks by both professional and amateur astronomers; night-time observing, through a variety of telescopes (feel free to bring your own telescopes ? the more the merrier!); and a telescope trail

The talks, on a wide variety of astronomical topics, will be held throughout the day and, in the event of bad weather, during the evening. The programme of talks is yet to be finalised but speakers already confirmed include: Professor Bill Williams, Professor Paul Delaney, Edwin Rodley, Stephen Chadwick, Nicholas Witte, JP Borberg. All talks will be accessible to a general audience.

Costs - StellarFest Fee: Applies to ALL attendees, including Day Visitors. People over 18 years $23.00, 10-18 years $12. Under 10s free. On-Site Accommodation: Shared heated Cabins (from twin to 8 per cabin) or Dormitory - $20 per night per person over 10 years old; $3 per night for under 10s.

For details of booking, facilities and alternative accommodation see http://www.horoastronomy.org.nz/upcoming-events/stellarfest If you have any queries please contact the HASI Secretary, Tina Hills, at: This email address is being protected from spambots. You need JavaScript enabled to view it..

4. Harry Williams Astrophotography Competition

Calling all Astrophotographers, the 2017 Harry Williams Astrophotography Competition is now open for entries, this year our judge is world-renowned planetary photographer Damian Peach, in 2010, Damian became the only Briton to win the prestigious Astronomy Photographer Of The Year Award for his composite photograph of Jupiter's moons, Ganymede and Io, orbiting the stormy surface of the Gas Giant.

Astronz has generously offered to sponsor the Deep Sky category with a Astronz $300 gift voucher as well as providing an Astronz beanie for the winner of each category!

Not only will the overall winner of the competition receive the coveted Harry Williams Astrophotography Trophy to adorn his or her mantelpiece for a year but they will also receive an OPTOLONG L-Pro light pollution filter worth $269 US dollars thanks to the very generous sponsorship of OPTOLONG Astronomical Filters.

As in previous years we are lucky to have Australian Sky & Telescope on board as sponsors of both the Solar System category and the Miscellaneous /Artistic category, the winners of these categories will receive a one year subscription to the magazine as well as the usual cash prize.

Also the winner of the Newcomers contest will receive a signed copy of 'Imaging the Southern Sky' by Steve Chadwick & Ian Cooper, more sponsors to be announced soon.

The competition cut-off date is August 31 and the competition awards will be announced at the annual Burbidge Dinner which is the Auckland Astronomical Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.

The competition rules and entry forms can be found on the Auckland Astronomical Society website http://www.astronomy.org.nz/new/public/default.aspx

-- From Jonathan Green's posting to the nzastronomers Yahoo group.

5. The Solar System in July

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.

The Earth is at aphelion, its greatest distance from the Sun for the year, on July 4 just before midday. The apparent diameter of the Sun will then be 31.46 arc-minutes, and its distance 152.1 million km, 1.016 astronomical units.

Sunrise, Sunset and Twilight Times in July

Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

                   July  1  NZST                  July 31  NZST
       SUN: rise: 7.45am,  set: 5.04pm    rise:  7.27am,  set: 5.27pm
Twilights    morning        evening           morning        evening
Civil:    starts: 7.16am, ends: 5.33pm   starts: 7.00am, ends: 5.55pm
Nautical: starts: 6.42am, ends: 6.00pm   starts: 6.27am, ends: 6.20pm
Astro:    starts: 6.08am, ends: 6.41pm   starts: 5.55am, ends: 7.00pm

July Phases of the Moon (times NZST, as shown by GUIDE)

          First quarter: July  1 at 12.51 pm (00:51 UT)
  Full moon:     July  9 at  4.07 pm (04:07 UT)
  Last quarter   July 17 at  7.26 am (Jul 16, 19:26 UT)
  New moon:      July 23 at  9.46 pm (09:46 UT)
  First quarter: July 31 at  3.23 am (Jul 30, 15:23 UT)

The Planets in July 2017

The second part of July will provide an excellent opportunity to view Mercury in the early evening sky. Jupiter is also best observed early evening, while Saturn is well placed all evening. Venus remains the obvious brilliant morning "star". Mars is too close to the Sun to see all month.

MERCURY is an evening object and will be best placed for viewing at the end of the month. It sets 45 minutes after the Sun on the 1st, so will then be rather low for viewing as the sky darkens. By mid-July the planet will set just after 7 pm, nearly 2 hours after the Sun. At 6 pm, 45 minutes after sunset, Mercury, magnitude -0.2, will be almost 10° above the horizon in a direction some 30° to the north of west.

By the end of July, Mercury will be even easier to see, some 15° up 50 minutes after sunset. Regulus, at 1.4 a magnitude fainter than Mercury, will be about 6° below the planet. On the 25th Mercury, now at magnitude +0.2, will be 1.2° to the left of the star, with the latter slightly higher. On that evening the crescent moon, 4.4% lit, will be less than 3° below Mercury. The following evening, the 26th, will find Mercury just over 1° from Regulus now slightly higher than the star. The moon will be 10° above the pair.

VENUS remains an easy morning object during July. It rises about 3.5 hours before the Sun on the 1st, reducing to 2.5 hours earlier on the 31st. During July, Venus makes its way across Taurus, passing between the Pleiades and Aldebaran. At their closest, on the morning of the 14th, the planet will be 3° to the lower left of 1st magnitude Aldebaran. Venus will of course completely outshine Aldebaran, by 5 magnitudes.

On the morning of the 21st, the crescent moon will be just under 5° to the lower right of Venus. The previous morning the moon will be a little less than 3° to the left of Aldebaran. The end of July will find Venus in the most northerly part of Orion, some 15° to the lower left of Betelgeuse.

MARS is not observable during July. It finally reaches conjunction with the Sun on the 27th of July. It will then be 1.64 AU beyond the Sun and 397 million km, 2.66 AU, from the Earth.

JUPITER will remain a prominent early evening object during July. It sets at 1am on the 1st and a few minutes after 11pm on the 31st, so will then be getting a little low and to the west by mid evening. The planet will be a few degrees below Spica.

The moon, at first quarter, will be 3° to the lower right of Jupiter on the 1st. It passes Jupiter again on July 28/29. As seen from NZ, the moon will be just over 8° below Jupiter on the 28th and some 6° to the upper right of the planet on the 29th. Their closest approach is a few minutes before noon on the 28th, when the two are 3° apart. This will be about the time Jupiter rises for NZ.

SATURN will be well placed for evening viewing during July. It rises at 3.45 pm on the 1st and two hours earlier by the 31st, giving it a good altitude an hour after sunset. The planet will be moving rather slowly to the west through Ophiuchus. The moon, two days short of full, will be 4° from Saturn as seen early evening in NZ. The separation of the two will increase during the evening as the moon moves away to the east.

Outer Planets

URANUS is a morning object in Pisces during July. It rises about 2 am on the 1st and at midnight on the 31st. The planet is at magnitude 5.8 throughout the month.

NEPTUNE rises at 10.15 pm on July 1 and two hours earlier on the 31st. It is in Aquarius at magnitude 7.9.

PLUTO, magnitude 14.4, is at opposition on July 10. It will then rise close to the time of sunset and set close to the time of sunrise. The planet will remain in Sagittarius and will be 1.3° from the magnitude 2.9 star, pi Sgr, by the end of the month.

Minor Planets

(1) CERES in the morning sky, starting July in Taurus only 14° from the Sun, too close for observation. It moves into Gemini on the 11th and by the end of the month 2° from the 3.0 magnitude star epsilon Gem. Ceres, with a magnitude 9.0, will then rise 100 minutes before the Sun

(4) VESTA is in Leo during July at magnitude 8.2. Its path through Leo takes the asteroid past Regulus. The two are just over 4° apart at their closest on July 18. Vesta sets at 10.30 pm on July 1 and 7.40 pm on the 31st.

(6) Hebe, in Ophiuchus, fades from magnitude 9.3 to 9.7 during July. It rises just before sunset on the 1st.

(7) Iris is in the morning sky with a magnitude 9.7 on the 1st and 9.2 on the 31st. The asteroid is in Pisces and rises at 12.30 am on the morning of July 31.

-- Brian Loader

6. Potential Meteor Shower

Earth crosses a dust trail from comet C/2015 D4 (Borisov) on July 29 at 00:22 UT (solar longitude 125.858 deg). Unfortunately that is noon on July 30 in NZ, not a good time for looking for meteors. Anyone running a radio-detection system for meteors, or observers in the dark at other longitudes, should check for the shower. The shower is expected to radiate from R.A. = 79 deg = 5h 16m, Dec. = -32 deg, with geocentric velocity 45.9 km/s.

The shower prediction is by Peter Jenniskens, SETI Institute and NASA Ames Research Center, and E. Lyytinen, Helsinki, Finland using an improved comet orbit. It was published in IAU Central Bureau Electronic Telegram No. 4403, 2017 June 13.

7. First PhD prize Winners Announced by the IAU

In 2016 the International Astronomical Union initiated a new annual competition to find the best PhD theses in astronomy. Up to ten prizes can be offered each year, being one for each of the nine IAU divisions and an additional prize for a graduate student from a developing country.

The first round of prize winners has just been announced. See https://www.iau.org/news/announcements/detail/ann17024/

The nine winners will receive free registration at the next IAU General Assembly in Vienna in August 2018, plus support for their travel to Vienna.

Another round in the PhD prize competition will take place this year, with submissions due by December 15. Details are to be found at https://www.iau.org/news/announcements/detail/ann16044/

-- John Hearnshaw, President, IAU Division C, Astronomy education, outreach and heritage

8. Variable Star News

The AAVSO website hosts a Long Period Variable (LPV) Section, which is currently posting monthly articles ?LPV of the Month? This month?s issue features BH Crucis, which is a Southern Hemisphere Mira discovered in 1969 by R G Welsh. This is a particularly interesting Mira variable as its period has been observed to increase from 421 days in 1970 to 525 days in 1999, an increase of 104 days (20%) in only 12 cycles. The period has since slipped back somewhat to 505 days. The star deserves on-going visual and colour measurements. The magnitude range in V is 6.55 ? 10.1 The article mentions the 2009 paper by W S G Walker in Vol 37 (pp 87-95) of JAAVSO and three other references. An article was also published recently in July 2016 VSS Newsletter by Stan Walker on colour measurements of BH Crucis.

To find the LPV Section Monthly Features go to the LPV Section pages (address below) and find LPV of the month link on the menu RHS, https://www.aavso.org/aavso-long-period-variable-section which contains all the features posted in 2017.

-- Alan Baldwin

9. Setting up a Remote Observatory in Chile

Frustrated by the reduced number of observing nights on his island home of Rarotonga (40-50 fully clear nights/year, in 15 years reduced to less than 20/year as a result of changing weather patterns) Phil Evans decided to install an automated telescope in Chile. Why not! After a false start due to delays in construction of a roll-off roof set-up on a site at 2400 m, Phil took up with a company Obstech developing a slide-off roof complex at El Sauce, altitude just under 1600 m and at latitude 30.47°S, 26 km due south of the Gemini South installation (Gemini is a partnership of five Nth & Sth American countries and the Univ. of Hawaii which runs twin 8.1m diameter optical/infra-red telescopes).

After several delays in the completion date Phil and his wife took off in March 2016 to view the installation and install equipment. Disappointment again; the building was just the skeleton of the shed and certainly not yet ready to receive the equipment they had brought with them. However they did build the pier and installed the telescope mount. Some months later Phil?s equipment was installed by the Obstech team; ?first light? was 7 Oct 2016. Phil visited the site again in November 2016 and videos from this trip are available (links given) in his article. The article also describes in detail the equipment selected and the Kepler 2 work being undertaken by Phil. Some of the detail May be of interest to those setting up automated systems.

The newsletter account is both a travel saga as well as of astronomical interest; to read the full account, liberally illustrated with photos of telescopes and mountain views + videos, go to the January 2017 issue of the Variable Stars South Newsletter (VSS website https://www.variablestarssouth.org and look under the Community tab for Newsletters.

-- Alan Baldwin

10. LIGO's Third Gravity Wave Detection

The Laser Interferometer Gravitational-wave Observatory (LIGO) has made a third detection of gravitational waves, ripples in space and time, demonstrating that a new window in astronomy has been firmly opened. As was the case with the first two detections, the waves were generated when two black holes collided to form a larger black hole.

The newfound black hole, formed by the merger, has a mass about 49 times that of our Sun. This fills in a gap between the masses of the two merged black holes detected previously by LIGO, with solar masses of 62 (first detection) and 21 (second detection).

The new detection occurred during LIGO's current observing run, which began November 30, 2016, and will continue through the summer. LIGO is an international collaboration with members around the globe. Its observations are carried out by twin detectors -- one in Hanford, Washington, and the other in Livingston, Louisiana -- operated by Caltech and MIT with funding from the U.S. National Science Foundation (NSF).

LIGO made the first-ever direct observation of gravitational waves in September 2015 during its first observing run since undergoing major upgrades in a program called Advanced LIGO. The second detection was made in December 2015. The third detection, called GW170104 and made on January 4, 2017, is described in a new paper accepted for publication in the journal Physical Review Letters.

In all three cases, each of the twin detectors of LIGO detected gravitational waves from the tremendously energetic mergers of black hole pairs. These are collisions that produce more power than is radiated as light by all the stars and galaxies in the universe at any given time. The recent detection appears to be the farthest yet, with the black holes located about 3 billion light-years away. (The black holes in the first and second detections are located 1.3 and 1.4 billion light-years away, respectively.)

The newest observation also provides clues about the directions in which the black holes are spinning. As pairs of black holes spiral around each other, they also spin on their own axes -- like a pair of ice skaters spinning individually while also circling around each other. Sometimes black holes spin in the same overall orbital direction as the pair is moving -- what astronomers refer to as aligned spins -- and sometimes they spin in the opposite direction of the orbital motion. What's more, black holes can also be tilted away from the orbital plane. Essentially, black holes can spin in any direction.

The new LIGO data cannot determine if the recently observed black holes were tilted but they imply that at least one of the black holes May have been non-aligned compared to the overall orbital motion. More observations with LIGO are needed to say anything definitive about the spins of binary black holes, but these early data offer clues about how these pairs May form.

There are two primary models to explain how binary pairs of black holes can be formed. The first model proposes that the black holes are born together: they form when each star in a pair of stars explodes, and then, because the original stars were spinning in alignment, the black holes likely remain aligned.

In the other model, the black holes come together later in life within crowded stellar clusters. The black holes pair up after they sink to the centre of a star cluster. In this scenario, the black holes can spin in any direction relative to their orbital motion. Because LIGO sees some evidence that the GW170104 black holes are non-aligned, the data slightly favour this dense stellar cluster theory.

The study also once again puts Albert Einstein¹s theories to the test. For example, the researchers looked for an effect called dispersion, which occurs when light waves in a physical medium such as glass travel at different speeds depending on their wavelength; this is how a prism creates a rainbow. Einstein's general theory of relativity forbids dispersion from happening in gravitational waves as they propagate from their source to Earth. LIGO did not find evidence for this effect.

The LIGO-Virgo team is continuing to search the latest LIGO data for signs of space-time ripples from the far reaches of the cosmos. They are also working on technical upgrades for LIGO's next run, scheduled to begin in late 2018, during which the detectors' sensitivity will be improved. The hope is to see other types of astrophysical events soon, such as the violent collision of two neutron stars. For the full text, images and video see: http://ligo.org/ www.ligo.caltech.edu/ http://space.mit.edu/LIGO/index.html

-- From a NSF/Caltech/Massachusetts Institute of Technology (MIT) press release forwarded by Karen Pollard.

11. Early Earth Life Might Help Locate Mars Life

Fossil evidence of early life has been found in old hot spring deposits in the Pilbara, Western Australia, that date back almost 3.48 billion years. This extends the known evidence of life at land-based hot springs on Earth by about 3 billion years. Not only is the find exciting for what it might say about the evolution of early life on Earth, but it also has implications for the search for life on Mars. Our understanding of these deposits would not be possible without the foundations laid by earlier researchers.

In the late 1970s, fossilised stromatolites ? rock structures built by communities of microorganisms ? were discovered within these Pilbara deposits. These were interpreted as once living in a quiet, shallow water coastal environment much like we see in the modern setting of Shark Bay. But extensive research over the past 20 years has led to a much better understanding of the environment that suggests it was actually part of an ancient volcano.

In modern volcanic settings, hot fluids circulate in the rocks underground and manifest as hot vents at the bottom of the salty ocean, such as the black or white smokers, or terrestrial hot springs on land where fresh rainwater is available. What was unclear about the volcanic setting in the Pilbara was whether these hot circulating fluids were indeed discharging on land, producing hot springs ? such as those we see in Rotorua ? and could we link these hot springs to signs of life?

Our recent findings from the Pilbara, published in Nature Communications, provide a smoking gun to a terrestrial hot spring scenario in the form of a particular rock type called geyserite. This was found alongside a variety of textures that indicate life. Geyserite only forms around the edges of terrestrial hot spring pools and geysers. These are found actively forming today in New Zealand, Yellowstone National Park and Iceland to name a few.

The biological signatures that we?ve found include stromatolites, but also some newly identified microbial textures. This includes a microbial texture (called palisade fabric) that represents microbes that grew upon the ancient sinter terraces ? the rocks that form around hot spring pools. We also found evidence of gas bubbles that must have been trapped in a sticky substance (microbial) in order to be able to preserve the bubble shape. Spherical bubbles preserved in 3.48 billion year old rocks in the Dresser Formation in the Pilbara Craton in Western Australia provide evidence for early life having lived in ancient hot springs on land. Importantly, all of these textures are comparable to fossil textures found in modern hot spring settings such as Yellowstone National Park or Rotorua.

The Earth?s geological and fossil record is like a thousand-piece puzzle, but we only have a few pieces. Every missing piece we discover helps us to better shape our understanding of life. But these new findings don?t just extend back the record of geyserite and life living in hot springs on land by 3 billion years, they also indicate that life was inhabiting the land much earlier than previously thought, by up to 580 million years. Before these findings, the world?s oldest evidence for microbial life on land was from ancient, organic matter-rich soils from South Africa, aged between 2.7 billion and 2.9 billion years. The new discovery has implications for the evolution, and perhaps even the origin, of life on Earth.

Scientists are currently considering two hypotheses regarding the origin of life: that it began in the ocean in hot vents, or alternatively that it began on land in a version of Charles Darwin?s ?warm little pond? which was connected to a hot spring system. The discovery of biological signatures and fossil preservation in such ancient hot springs provides at least a geological perspective of the types of environments available and inhabited by life very early on in Earth?s history. This May lend weight to the hypothesis that life originated on land and then took a downhill adaptive evolutionary pathway to the salty ocean, whereas the opposite is typically proposed.

These findings have major implications regarding the search for life elsewhere in the universe, or at least our solar system. Our neighbouring planet, Mars, has long been a target in the search for extra-terrestrial life. It is widely accepted that the red planet was likely similar to Earth once upon a time, in that it had liquid water flowing on its surface and active volcanoes. Recent data from the spirit rover has even identified ancient hot springs, of a similar age to early Earth, in an area called Columbia Hills.

In fact Columbia Hills is one of the top three potential landing sites chosen for NASA?s upcoming Mars2020 rover that?s includes a primary objective to search for fossil life on Mars. Our findings imply that if life ever developed on the red planet, and it is preserved in ancient hot springs on Earth, then there is a good chance it could be preserved in ancient hot springs on Mars too.

-- From the article by Tara Djokic, a PhD research student at the University of New South Wales, at https://theconversation.com/evidence-of-ancient-life-in-hot-springs-on-earth-could-point-to-fossil-life-on-mars-77388 Thanks to Edwin Rod for passing along the link.

12. Two New Moons for Jupiter

The advent of monster telescopes equipped with super-sensitive, wide-field detectors has been a boon for astronomical discoveries, among them a bevy of tiny moonlets around the outer planets. For example, observations made from 2000 to 2003 yielded 46 moons around Jupiter ? more than two-thirds of the planet's total!

Now astronomer Scott Sheppard (Carnegie Institution for Science) has added two more to the planet's extended family, bringing the total of known moons to 69. The announcements for S/2016 J 1 and S/2017 J 1 ("S" for satellite, "J" for Jupiter) came via Minor Planet Electronic Circulars issued on June 2nd and June 5th, respectively.

As Sheppard explains, "We were continuing our survey looking for very distant objects in the outer solar system, which includes looking for Planet X, and Jupiter just happened to be in the area we were looking in 2016 and 2017." So they took a minor detour to image some fields that were very close to Jupiter.

With magnitudes hovering near 24, these barely-there moonlets must be only 1 or 2 km across. So for now all that's really known is the character of their orbits:

S/2016 J 1: Sheppard discovered this moonlet during an observing run on March 8, 2016, with the 6.5-m Magellan-Baade reflector at Las Campanas Observatory in Chile. Averaging 20,600,000 km from Jupiter, it's in an elongated orbit inclined 140° with an eccentricity of 0.14. It takes 1.65 years to orbit the planet.

Although Sheppard first sighted this moon last year, its orbit remained uncertain until he teamed up with David Tholen (University of Hawai'i) and Chadwick Trujillo (Northern Arizona University), who swept it up six weeks ago with the 8.2-m Subaru reflector on Mauna Kea.

S/2017 J 1: Sheppard and Trujillo recorded the second new find on March 23, 2017, using the venerable 4-m Victor Blanco reflector at Cerro Tololo Inter-American Observatory in Chile. It also turned up in images recorded with Subaru in 2016 and earlier this year, which allowed the team to confirm its existence. This moon likewise is far from Jupiter, at an average distance of 23,500,000 km. In this very elongated orbit, inclined 149° with an eccentricity of 0.40, the moonlet takes 2.01 years to go around Jupiter.

Both of these discoveries, as with the vast majority of Jupiter's moons, occupy retrograde orbits, with inclinations greater than 90°, meaning that they move in directions opposite that of the planet's spin. Such distant, irregular orbits imply that these bodies formed elsewhere in the outer solar system and were captured while passing by early in the planet's history.

According to an orbital assessment published in April by Marina Brozovi? and Robert A. Jacobson (Jet Propulsion Laboratory), 11 of Jupiter's irregular satellites have orbits known so poorly that they're considered "lost." Sheppard and his collaborators found all but one of those in 2003, and they haven't been observed since.

However, that's changing. The time Sheppard and Trujillo spent scrutinizing the region around Jupiter has already led to the recovery of S/2003 J 5, S/2003 J 15, and S/2003 J 18, as well as a better orbit for S/2011 J 2.

"We have for sure recovered five of the lost moons," Sheppard says, noting that the 2016 and 2017 observations could be easily linked to some of 2003's uncertain finds. "We have several more Jupiter moons in our new 2017 observations and likely have all of the lost moons in our new observations," he continues, but to ensure the identifications he'll need to return to those big telescopes for more observations in early 2018.

-- From Kelly Beatty's article on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/two-new-satellites-for-jupiter/?utm_source

The moons' orbits from M.P.E.C.s 2017-L46 and 2017-L47 S/2003 J 15 a = 0.1521 AU, e = 0.1945, i = 143.597, P = 1.92y, H = 16.7 S/2017 J 1 a = 0.1570 AU, e = 0.3969, i = 149.197, P = 2.01y, H = 16.5

13. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2017 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

14. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

For an application form contact the Executive Secretary This email address is being protected from spambots. You need JavaScript enabled to view it., Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

15. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants May be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 November 2016. Full details are set down in the RASNZ By-Laws, Section J. For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it. Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

16. Quote

"Physics is like sex. It May give some practical results but it's not why we do it." -- Richard Feynman in the Wall Street Journal.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
P.O. Box 57 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand

June 2017

Log in or become an RASNZ member to access this Southern Stars issue.

SWAPA 2017
John Drummond
Volume 56, number 2. June 2017. p3

 

The Louwman Collection of Historic Telescopes
William Tobin
Volume 56, number 2. June 2017. p6

 

The Norfolk Island Effect and the Whanagaroa Report
Grahame Fraser
Volume 56, number 2. June 2017. p11

 

Auckland Observatory Research in the First 25 Years - A Personal View II
Stan Walker
Volume 56, number 2. June 2017. p18

 


The Government recently introduced new laws on high-power laser pointers. These devices are useful tools for astronomers to use in observatories or to point out things in the night sky. If you are involved in astronomy and use a laser pointer then you should understand the new controls and how they apply to you.

What devices are covered by the new laws?

Laser pointers are small hand-held devices that emit a tightly focused beam of light that can be concentrated onto a very small area even over long distances. Although the total power in the beam may be small (a few milliwatts), concentrating this power onto a tiny spot creates a point of very high intensity.

The new laws define a high-power laser pointer as a device that:

  1. in the Director-General of Health’s opinion, is of the kind commonly known as a laser pointer; and
  2. b. is battery operated; and
  3. is designed or intended to be operated while held in the hand; and
  4. produces a coherent beam of optical radiation of low divergence (i.e., the beam does not fan out like a torch beam); and
  5. has a power output of greater than 1 milliwatt (mW).

Note: the new laws DO NOT cover laser pointers that are 1 mW or less in power. Some other laser devices are also exempt (e.g., surveying equipment).

Why were the new controls introduced?

The controls were introduced to manage the health and safety risks from high-power laser pointers. There are two main risks from these devices.

People may not be aware of the potential harm these devices can cause and inadvertently shine them in their own eyes or other people’s eyes.

People maliciously (or ignorantly) shine them at vehicles such as aircraft and dazzle the pilot. Even when shone from several hundred meters away high-power laser pointers can dazzle and cause temporary flash blindness. Distracting or dazzling a pilot in this way for instance, is a serious aviation safety risk, particularly during critical phases of flight such as during critical phases of flight such as during take-off and/or landing. Car drivers, cyclists, and ship crews are also at risk if dazzled by high-power laser pointers.

What do the laws do?

The new controls cover the importation, sale/supply and acquisition of high-power laser pointers (devices that have a power of greater than 1 milliwatt (mW)). In summary:

The Custom Import Prohibition (High-power Laser Pointers) Order 2013 restricts the importation of high-power laser pointers to those people who have obtained authorisation to import them from the Director-General of Health.  

The Health (High-power Laser Pointers) Regulations 2013 restrict the sale/supply of high-power laser pointers to those who are authorised suppliers and also restrict the acquisition of such devices to those who are authorised recipients.

To become an authorised importer, supplier or recipient of a high-power laser pointer most people need to apply to the Director-General of Health using an application form available on the Ministry of Health’s website (there are some exceptions as described below).

What do the new laws mean for astronomy societies and their members?

Astronomy societies and their members DO NOT have to get permission to supply or acquire high-power laser pointers because the government recognises that they have a legitimate use for such devices. (Note that “supply” means both “sell” and “give for free”.) Astronomy societies and their members still need to apply for permission to import them, however.

Under the new controls the Director-General has declared that certain classes of people are approved suppliers or recipients. This means they are exempted from having to specifically apply for permission to acquire or supply such devices. Astronomy societies and their members are one of the few such approved classes of people (other approved classes include those who use laser pointers for scientific, research, or industrial purposes).

The ability to have such approved classes of persons recognises that some people have legitimate uses for such devices, will better understand their risks, take appropriate precautions to use and store devices safely, and will be unlikely to misuse their laser pointers (i.e., they will not shine them at aircraft or intentionally shine them at people).

The new controls do have some impacts on astronomy societies and their members. The key ones are noted below:

If you want to import any high-power laser pointer you will need to complete an application form, send it to the Ministry of Health, and receive an authorisation to import. You need to obtain import consent BEFORE you import the device (otherwise it will likely be seized by Customs and you will have to seek a review of seizure).

You also need to be careful that you do not supply any high-power laser pointer to any person who is not authorised to acquire one. While you are entitled to supply a device to other members of an astronomy society (who are also entitled to receive them without seeking permission), you cannot automatically supply a high-power laser pointer to anyone. For example, you cannot simply give or sell your high-power laser pointer to any member of the public if they have not received an authorisation from the Ministry of Health or are part of an approved class.

The Regulations contain offences and penalties. For example, supplying a device to another person without having reasonable grounds to believe that the person is authorised to receive it is a breach of the Regulations, and you will be liable to pay a fine.

If you wish to buy a high-power laser pointer from a New Zealand-based supplier, you will need to provide them some proof that you belong to an approved class of persons. For example, you could show them a letter from your astronomy Society, on headed paper, confirming that you are a bona fide member.

Are any other controls on laser pointers being considered?

Yes. The controls mentioned above DO NOT cover possession of laser pointers. That is, people do not have to get any authorisation to possess laser pointers that they already own. However, a proposed law change is currently being considered by Parliament. The Summary Offences (Possession of Hand-held Lasers) Amendment Bill is proposing to make it an offence to be in possession of a high-power laser pointer in a public place without having a reasonable excuse. A similar offence currently exists for knives.

Even if this proposed law change is passed by Parliament then astronomers are unlikely to be adversely impacted. Being an approved class of person, entitled to acquire high-power laser pointers under the regulations noted above, and having a legitimate reason to have a laser pointer will provide a ‘reasonable excuse’ (unless the devices are being misused).

Ultimately, however, Parliament will decide whether the Bill is passed into law.

Where do I get more information?

More information about laser pointers, the new controls and their implications for you, and how to apply for authorisation is available on the Ministry of Health’s website: http://www.health.govt.nz/our-work/environmental-health/high-power-laser-pointers

You can also email any questions on the new controls to This email address is being protected from spambots. You need JavaScript enabled to view it.

RASNZ Electronic Newsletter April 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 196

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. A Habitable Super-Earth?
2. RASNZ Conference Paper Submissions
3. Harry Williams Astrophotography Competition
4. The Solar System in May
5. Comet C/2015 ER61 (PANSTARRS) Flaring
6. Variable Star News
7. Atmosphere Detected Around Super-Earth
8. Escapee from Stellar Break-up Found
9. Jupiter Close-up from Hubble
10. Cassini's 'Grand Finale'
11. NASA Image and Video Archive
12. NASA Surveys Space-borne Laser Danger
13. How to Join the RASNZ
14. Gifford-Eiby Lecture Fund
15. Kingdon-Tomlinson Fund
16. Quotes

1. A Habitable Super-Earth?

An exoplanet orbiting a red dwarf star 40 light-years from Earth May be the new holder of the title "best place to look for signs of life beyond the Solar System". Using several telescopes around the world, an international team of astronomers discovered a "super-Earth" orbiting in the habitable zone around the faint star LHS 1140. This world is a little larger and much more massive than the Earth and has likely retained most of its atmosphere. This, along with the fact that it passes in front of its parent stars as it orbits, makes it one of the most exciting future targets for atmospheric studies. The results appear in the 20 April 2017 issue of the journal Nature.

The newly discovered super-Earth LHS 1140b orbits in the habitable zone around a faint red dwarf star, named LHS 1140, in the constellation of Cetus. Red dwarfs are much smaller and cooler than the Sun. So, although LHS 1140b's distance from its star is one-tenth Earth's distance from the Sun, it receives only about half as much sunlight from its star as Earth gets from the Sun. This puts LHS 1140b in the middle of the habitable zone, where liquid water can exist. The orbit is seen almost edge-on from Earth so the exoplanet passes in front of the star every 25 days, dimming it slightly.

The astronomers estimate the age of the planet to be at least five billion years. They also deduced that it has a diameter 1.4 times larger than the Earth - almost 18 000 kilometres. But with a mass around seven times greater than the Earth, and hence a much higher density, it implies that the exoplanet is probably made of rock with a dense iron core.

For life as we know it to exist, a planet must have liquid surface water and retain an atmosphere. When red dwarf stars are young, they are known to emit radiation that can be damaging for the atmospheres of the planets that orbit them. In this case, the planet's large size means that a magma ocean could have existed on its surface for millions of years. This seething ocean of lava could feed steam into the atmosphere long after the star has calmed to its current, steady glow, replenishing the planet with water.

This super-Earth May be the best candidate yet for future observations to study and characterise its atmosphere, if one exists. In particular, observations coming up soon with the NASA/ESA Hubble Space Telescope will be able to assess exactly how much high-energy radiation is showered upon LHS 1140b, so that its capacity to support life can be further constrained. Further into the future - when new telescopes like European Southern Observatory's Extremely Large Telescope are operating - it is likely that we will be able to make detailed observations of the atmospheres of exoplanets, and LHS 1140b is an exceptional candidate for such studies.

See the Nature letter at https://www.eso.org/public/archives/releases/sciencepapers/eso1712/eso1712a.pdf

-- From a European Southern Observatory press release eso1712 forwarded by Karen Pollard.

2. RASNZ Conference Paper Submissions

As you will know, the next conference of the Royal Astronomical Society of New Zealand (RASNZ) will be held in Dunedin over the weekend of 12th -14th May 2017.

The oral programme for the conference is now full, but we can still accept poster papers. If you want your poster to appear in the printed programme please use the submission form on the RASNZ Conference website www.rasnz.org.nz/Conference, or email titles/abstracts to me directly at This email address is being protected from spambots. You need JavaScript enabled to view it. before April 30th. A full list of accepted titles and abstracts is being maintained on the RASNZ Conference website.

TTSO11 paper submissions

Following the conference, the 11th Trans-Tasman Symposium on Occultations (TTSO11) will be held at the conference venue on Monday/Tuesday 15th - 16th May. Details of the registration for TTSO11 are available with the registration form for the conference, and paper submissions should be sent directly to the convenor Murray Forbes (This email address is being protected from spambots. You need JavaScript enabled to view it.). As workshops will be held on analysing and reporting your results, please bring along a laptop with your occultation programs and any recordings you'd like us to analyse with you. -- Warwick Kissling and Murray Forbes, RASNZ Standing Conference Committee.

3. Harry Williams Astrophotography Competition

Calling all astrophotographers. The 2017 Harry Williams Astrophotography Competition is now open for entries.

This year our judge is world-renowned planetary photographer Damian Peach. In 2010 Damian became the only Briton to win the prestigious Astronomy Photographer of the Year Award for his composite photograph of Jupiter's moons, Ganymede and Io, orbiting the stormy surface of the Gas Giant.

Damian is arguably the world's most well-known planetary photographer, his high resolution images of the planets have been compared in quality to the kind of images captured by orbiting spacecraft! So we are truly lucky to have Damian on board as our judge for this year's competition.

As in previous years we are lucky to have Australian Sky & Telescope on board as sponsors of both the Solar System category and the Miscellaneous / Artistic category, the winners of these categories will receive a one year subscription to the magazine as well as the usual cash prize. Also the winner of the Newcomers contest will receive a signed copy of 'Imaging the Southern Sky' by Stephen Chadwick & Ian Cooper. More sponsors to be announced soon.

The competition cut-off date is the 31st of August and the competition awards will be announced at the annual Burbidge Dinner which is the Auckland Astronomical Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.

The competition rules and entry forms can be found on the Auckland Astronomical Society website http://www.astronomy.org.nz/new/public/default.aspx

I'm looking forward to seeing all your images and wishing you all clear skies.

--From Jonathan Green's posting to the nzastronomers Yahoo group.

4. The Solar System in May

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.

Sunrise, sunset and twilight times in may

        Times are for Wellington.  They will vary by a few minutes elsewhere in 
NZ.
                   May  1  NZST                    May 30  NZST
       SUN: rise: 7.05am,  set: 5.30pm     rise: 7.33am, set:  5.03pm 
Twilights     morning       evening            morning       evening
Civil:    starts: 6.39am, ends: 5.56pm   starts: 7.05am, ends: 5.31pm
Nautical: starts: 6.06am, ends: 6.29pm   starts: 6.31am, ends: 6.08pm
Astro:    starts: 5.34am, ends: 7.01pm   starts: 5.58am, ends: 6.39pm

May PHASES OF THE MOON (times NZST, as shown by GUIDE)

          First quarter: May  3 at  2.47 pm (2:47 UT)
  Full moon:     May 11 at  9.43 am (May 10, 21:43 UT)
  Last quarter   May 19 at 12.33 pm (00:33 UT)
  New moon:      May 26 at  7.45 am (May 25, 19:45 UT)

Occultation Of Regulus

A lunar occultation of Regulus on May 4 is visible from New Zealand and Australia. The disappearance is at the ?dark? limb of the moon so readily observable in binoculars. It will be just before sunset at Perth in Western Australia but should be observable there. Elsewhere, further east, the occultation will be after the Sun has set.

The reappearance from occultation will be at the sunlit limb of the moon, making it a little more difficult to observe and time accurately.

Disappearance times in New Zealand range from 10.40 pm in the southwest to 10.53 pm at East Cape. The corresponding range of reappearance times is 11.47 pm to 11.58 pm. Observers should generate their local predictions using Dave herald?s Occult program to obtain precise time predictions for their own locality.

The planets in may 2017

Jupiter will be prominent in the evening sky with Saturn appearing later to the east. Mars is getting too close to the Sun for easy observation. Mercury will be at its morning sky best for the year in the 2nd part of the month, well placed an hour before sunrise. It will very much outshone by Venus some way above it.

MERCURY, in the morning sky, rises 90 minutes before the Sun on May 1 and nearly 2 hours earlier than the Sun at the end of the month. With a low altitude and a magnitude 2.4 the planet will not be readily observable at the beginning of May.

Things rapidly improve during the first half of May as Mercury brightens and moves further from the Sun. The planet reaches its greatest elongation, 26° west of the Sun mid month. On the morning of May 18 at 6.20 am, hour before sunrise at Wellington, Mercury will be nearly 13° above the horizon with a magnitude 0.4. Venus will be some 19° above and a little to the left of the fainter planet. The middle of May will give the best opportunity to observe Mercury in the morning sky this year. By the end of May the planet will be brighter at magnitude -0.3 but getting little lower.

Mercury stars May in Pisces, it crosses a corner of Cetus between May 19 and 22 before entering Aries. On the morning of May 24 a thin crescent moon will be 3.5° above Mercury

VENUS is an easy to find morning object in May. It rises over 3 hours before the Sun on the 1st increasing to almost 4 hours earlier by the 31st. Venus is following Mercury across Pisces and ends May quite close to the position in the stars that Mercury was in at the beginning of the month.

On the morning of the 23rd the crescent moon will be about 3.5° to the lower right of Venus. On 31st, Venus will also be 3.5° above Uranus, so the two will be visible in a 5° binocular field.

MARS slowly gets lower in the early evening sky. At magnitude 1.6 to 1.7 and a low altitude it will be a difficult object in the twilight. It sets 75 minutes after the Sun on the 1st, an hour after the Sun on the 31st.

On the evening of the 27th a very thin crescent moon will be about 4.5° above Mars. But at 5.45 pm when the Sun is only 8° below the horizon, Mars? altitude at Wellington will be slightly less than 4°

JUPITER will be a prominent object throughout the evening sky following its opposition at the beginning of April. Early evening in May will find the planet just under 10° to the left of the first magnitude star Spica, alpha Virginis. Some 8 hours later the anticlockwise rotation of the sky will bring Spica to a position directly above Jupiter.

The nearly full moon will be 5° to the lower right of Jupiter on May 8.

SATURN will rise at 8 pm on the 1st of May and a good 2 hours earlier by the 31st. It brightens slightly during the month from 0.3 to 0.1 making it the brightest object to the east. There are a number of the brighter, 2nd magnitude stars in Sagittarius some 10 to 20° to its Saturn?s left.

The planet itself starts the month in Sagittarius. It moves only slowly to the west through the stars, less than 2° during the month. Even so this is sufficient to take it into Ophiuchus mid month.

Currently Saturn is 22° south of the equator. As a result when due north it will be very high in NZ skies. This will be about 3.30 am early May, advancing to 1.30 late May.

The moon, a little past full, will be some 7° from Saturn on the evenings of May 13 and 14. The position of the moon with reference to Saturn on the two night will be very different. Moon and planet are closest about 10 am on the morning while they are below the horizon for NZ.

Outer Planets

URANUS begins to move up into the morning sky shortly before sunrise, following its conjunction with the Sun mid April. At the beginning of May Uranus will be close to Mercury but too low for easy observation. At the end of May a much brighter marker, Venus, will be 3° above the outer planet. By then Uranus will rise just before 4 am, with Venus rising 15 minutes earlier. So at 6.30 am, an hour before sunrise, the two will be at a comfortable 25° altitude.

NEPTUNE rises early into the morning sky, soon after 2am on May 1 and 2 hours earlier on May 31. The planet remains in Aquarius at magnitude

7.9, moving only half a degree during the month. On the 1st it will be
18.5° above and a little left of Venus.

PLUTO, magnitude 14.4, is moving into the evening sky rising at 9.40 pm on the 1st, 2 hours earlier on the 31st. It will remain in Sagittarius about 2.5° from the 2.9 magnitude star pi Sgr.

Minor Planets

(1) CERES, in Taurus is too close to the Sun to observe in May. It is at conjunction early June.

(4) VESTA is in Cancer during May with a magnitude changing from 8.0 to 8.2. On the 1st it sets about 10.20pm. By the 31st it will be setting about an hour earlier. The moon will be just over 6° above Vesta in May 2. It will be in a similar position again, compared to Vesta, on the 30th but about half a degree closer.

-- Brian Loader

5. Comet C/2015 ER61 (PANSTARRS) Flaring

This long-period comet has brightened unexpectedly to total magnitude 6, bright enough to see in binoculars. It is low in the eastern dawn sky. Below are positions for the next 20 days. No magnitude predictions are included but the comet May stay around 6-7th magnitude for the duration.

Positions at 5 a.m NZST for April-May dates
    R.A. (2000) Dec.          R.A. (2000) Dec. 
     h  m  s    °  '           h  m  s     °  '
21  22 07 40  -07 12       1  22 54 26  -01 58 
22  22 12 28  -06 41       2  22 58 56  -01 27 
23  22 17 15  -06 09       3  23 03 25  -00 56 
24  22 22 00  -05 38       4  23 07 51  -00 25 
25  22 26 44  -05 06       5  23 12 15  +00 05 
26  22 31 25  -04 35       6  23 16 38  +00 36 
27  22 36 05  -04 03       7  23 20 58  +01 05 
28  22 40 43  -03 31       8  23 25 16  +01 35 
29  22 45 19  -03 00       9  23 29 32  +02 05 
30  22 49 54  -02 29      10  23 33 46  +02 34

6. Variable Star News

The American Association of Variable Star Observers (AAVSO) maintains an International Variable Star Index (VSX). Ever wondered how stars make it into this catalogue? The latest AAVSO Newsletter (No 72, 2017 April) has an article on identifying a new variable star and submission to the AAVSO for addition to the VSX. This is an updated Policy Document and gives detailed advice on the work required, and information recommended, to smooth the way to acceptance of your submission. AAVSO Quarterly Newsletter address https://www.aavso.org/aavso-newsletter

7. Atmosphere Detected Around Super-Earth

Astronomers have detected an atmosphere around the super-Earth GJ 1132b, the first detection of an atmosphere around a low-mass super- Earth. In terms of radius and mass GJ 1132b is the most Earth-like planet around which an atmosphere has yet been detected. It has mass 1.6 times Earth's mass and a diameter of 1.4 Earth's. It orbits the red dwarf star GJ 1132 in the southern constellation Vela, 39 light-years from us.

GJ 1132b is a transiting planet. As seen from Earth, it passes directly in front of its star every 1.6 days, blocking some of the star's light. These transits were observed in seven different wavelength bands simultaneously with a 2.2-metre telescope at the European Southern Observatory in Chile. The size of stars like GJ 1132 is well known from stellar models. From the fraction of starlight blocked by the planet, astronomers can deduce the planet's size. Crucially, the new observations showed the planet to be larger at one of the infrared wavelengths than at the others. This suggests the presence of an atmosphere that is opaque to this specific infrared light, making the planet appear larger, but transparent at all the others. Different possible versions of the atmosphere were then simulated by team members at the University of Cambridge and the Max Planck Institute for Astronomy. According to those models, an atmosphere rich in water and methane would explain the observations very well.

Astronomers' current strategy for finding life on another planet is to detect the chemical composition of that planet's atmosphere then check for certain chemical imbalances that require the presence of living organisms for an explanation. In the case of our own Earth, the presence of large amounts of oxygen is such a trace.

The discovery comes with the usual exoplanet caveats: while somewhat larger than Earth, and with 1.6 times Earth's mass (as determined by earlier measurements), observations to date do not provide sufficient data to decide how similar or dissimilar GJ 1132b is to Earth. Possibilities include a "water world" with an atmosphere of hot steam.

The presence of the atmosphere is a reason for cautious optimism. M dwarfs are the most common types of star. They show high levels of activity like flares and particle streams. In some cases this activity is expected to blow away nearby planets' atmospheres. GJ 1132b provides a hopeful counterexample of an atmosphere that has endured for billions of years (that is, long enough for us to detect it). Given the great number of M dwarf stars, such atmospheres could mean that the preconditions for life are quite common in the universe.

In any case, the new observations make GJ 1132b a high-priority target for further study by instruments such as the Hubble Space Telescope, ESO's Very Large Telescope, and the James Webb Space Telescope slated for launch in 2018.

For the original text and images see http://www.mpia.de/news/science/2017-03-GJ1132b

-- From a Max Planck Institute for Astronomy press release forwarded by Karen Pollard.

8. Escapee from Stellar Break-up Found

In the search for rogue planets and failed stars astronomers using the NASA/ESA Hubble Space Telescope have created a new mosaic image of the Orion Nebula. During their survey of this famous star formation region, they found what May be the missing piece of a cosmic puzzle; the third, long-lost member of a star system that had broken apart.

The Orion Nebula is the closest star formation region to Earth, only 1400 light-years away. It is a turbulent place ? stars are being born, planetary systems are forming and the radiation unleashed by young massive stars is carving cavities in the nebula and disrupting the growth of smaller, nearby stars.

Because of this ongoing turmoil, Hubble has observed the nebula many times to study the various intriguing processes going on there. The latest survey produced a large composite image of the nebula?s central region, combining visual and near-infrared data.

Astronomers used the new infrared data to hunt for rogue planets ? free-floating in space without a parent star ? and brown dwarfs in the nebula. The infrared capabilities of Hubble also allow it to peer through the swirling clouds of dust and gas and see hidden stars. The unveiled stars are bright red in the final image.

By comparing observations made in 1998 with the recent ones astronomers found a star moving at an unusually high speed ? about 200 000 kilometres per hour. That's almost 30 times the speed of most of the nebula?s stellar inhabitants. This star could be the missing piece of the puzzle of a star system that had been broken apart 540 years ago.

Astronomers already knew about two other runaway stars in the Orion Nebula which were most likely once part of a now-defunct multiple-star system. For years it was suspected that the original system contained more than just these two stars. Now Hubble May have found the missing third piece of this cosmic puzzle.

Whether the new star is indeed the missing ? and the last ? piece of the puzzle will require further observations. So will the answer to the question of why the original star system broke apart in the first place. While there are several theories ? interactions with other, nearby stellar groups, or two of the stars getting too close to each other ? none can be ruled out or confirmed yet.

For the original text and images see http://hubblesite.org/news_release/news/2017-11

-- From a Space Telescope press release forwarded by Karen Pollard.

9. Jupiter Close-up from Hubble

During April 2017 Jupiter is in opposition: it is at its closest to Earth and the hemisphere facing Earth is fully illuminated by the Sun. On April 7 Jupiter was 670 million kilometres so that it appears brighter in the night sky than at any other time in the year. This event allows astronomers using telescopes in space and on the ground to see more detail in the planet's atmosphere.

On 3 April Hubble took advantage of this favourable alignment and turned its sharp eye towards Jupiter to add to the collection of images of our massive neighbour. Hubble observed Jupiter using its Wide Field Camera 3 (WFC3), which allows observations in ultraviolet, visible and infrared light. The final image shows a sharp view of Jupiter and reveals a wealth of features in its dense atmosphere. As it is so close, Hubble can resolve features as small as about 130 kilometres across. [That's about 0.04 second of arc! - Ed.]

The surface of Jupiter is divided into several distinct, colourful bands, running parallel to the equator. These bands are created by differences in the opacity of the clouds which have varying quantities of frozen ammonia in them; the lighter bands have higher concentrations than the darker bands. The differing concentrations are kept separate by fast winds which can reach speeds of up to 650 kilometres per hour. The most recognisable feature on Jupiter is the huge anticyclonic storm, called the Great Red Spot ? this storm is large enough to engulf a whole Earth-sized planet at once. However, as with the last images of Jupiter taken by Hubble and telescopes on the ground, this new image confirms that the huge storm which has raged on Jupiter?s surface for at least 150 years continues to shrink. The reason for this is still unknown. So Hubble will continue to observe Jupiter in the hope that scientists will solve this stormy riddle.

Next to the famous Great Red Spot a much smaller storm can be seen at farther southern latitudes. Because of its similar appearance but much smaller size it was dubbed ?Red Spot Junior?.

The observations of Jupiter form part of the Outer Planet Atmospheres Legacy (OPAL) programme, which allows Hubble to dedicate time each year to observing the outer planets. This way scientists have access to a collection of maps, which helps them to understand not only the atmospheres of the giant planets in the Solar System, but also the atmospheres of our own planet and of the planets that are being discovered around other stars. The programme began in 2014 with Uranus, and has been studying Jupiter and Neptune since 2015. In 2018, it will begin viewing Saturn.

For the original text and image links see http://hubblesite.org/news_release/news/2017-15

-- From a NASA/ESA press release forwarded by Karen Pollard.

10. Cassini's 'Grand Finale'

On April 4 NASA held a news conference at the agency's Jet Propulsion Laboratory in Pasadena to preview the beginning of Cassini's final mission segment, known as the Grand Finale, which begins in late April.

Cassini has been orbiting Saturn since June 2004, studying the planet, its rings and its moons. A final close flyby of Saturn's moon Titan on April 22 will reshape the Cassini spacecraft's orbit so that it begins its final series of 22 weekly dives through the unexplored gap between the planet and its rings. The first of these dives is planned for April 26. Following these closer-than-ever encounters with the giant planet, Cassini will make a mission-ending plunge into Saturn's upper atmosphere on Sept. 15.

For graphics, video and background information about Cassini's Grand Finale see http://saturn.jpl.nasa.gov/grandfinale

-- From a NASA JPL press release forwarded by Karen Pollard

11. NASA Image and Video Archive

In a win for space enthusiasts and history buffs alike, NASA unveiled a new, searchable image and video archive on Tuesday, showcasing 140,000 images. (More: Haunting Photos of Abandoned NASA Sites) The new library consolidates over 60 collections previously featured, spanning the agency's founding in 1958 to the most recent images from space. "The library is not comprehensive, but rather provides the best of what NASA makes publicly available from a single point of presence on the web," NASA officials said.

Space-lovers should stay tuned as the library will continue to grow. Click through the slideshow above for some of NASA's most popular images. Link given goes to https://images.nasa.gov/#/

-- From Spaceweather 31 March https://weather.com/photos/news/nasa-releases-new-image-video-libraryforwarded by Alan Baldwin.

12. NASA Surveys Space-borne Laser Danger

Maurice Collins points out that NASA is doing a survey of telescope usage amid concerns about space-borne lasers that look downward. The survey us at https://goo.gl/forms/E7n4Xrvp3oQqmCYn1

This note is from the end of the survey: Thank you so much for taking the time to respond to this survey! We're conducting this survey as part of a probabilistic risk assessment of the potential hazards presented to the general public by spaceborne lidar systems. NASA and its partners (including CNES and ESA) use lidar on satellites to make measurements of Earth's surface and atmosphere. Examples include CALIPSO, CATS, ALADIN, and GLAS. Lidar works on the same time-of-flight principle as radar, but using a laser instead of a beam of radio radiation.

The lidar lasers on satellites greatly exceed eye safety standards for observers on the ground for direct, unaided viewing of the laser beam. But, with sufficiently powerful light-collecting optics, it would, in theory, be possible to exceed the retinal damage threshold. So please, NEVER LOOK DIRECTLY INTO A LASER WITH YOUR EYE. We really don?t want to injure anyone! To that end, we're attempting to calculate the odds of one of these lasers causing injury to make sure the risk has been mitigated to an acceptably low level (e.g. lower than the odds of being injured by a piece of orbital debris from the satellite itself when it reenters Earth?s atmosphere someday, which is another risk we must calculate and mitigate to internationally-agreed-upon acceptably low levels).

We?ve so far done our best to model the problem, but many of our input parameters are only educated guesses. For instance, while we can calculate the energy per area that would result from standing in the laser footprint and viewing the beam through a given size and type of telescope, we don?t know how many such telescopes are in use at any given time. Larger telescopes carry a higher risk of injury, but we suspect larger telescopes are less common since they cost more. And if someone is doing all-night observations, we suspect it?s more likely that they?re using a sensor/camera rather than their eye, e.g. for recording star trails or doing long exposures of faint objects.

The particular orbital parameters of our various satellites also affect our modeling. A laser on the ISS has a non-repeating ground track that paints the mid-latitudes but never the polar latitudes and can pass overhead at different times of night. The A-Train constellation of satellites, on the other hand, has a repeating ground track, flies in a solar-synchronous orbit, so it paints all latitudes and always passes overhead at approximately the same time of night. So, the odds of injuring someone depend on things like the percentage of people still out observing at 2 am and whether active astronomers are distributed by latitude in proportion to the overall population.

If you decide this is a phenomenon you want to see for yourself, be sure to make your attempt using a camera rather than your eye; if you are successful, not only will you avoid the risk of retinal damage by using a camera, you'll also have an image to prove you saw the laser flash. A picture is much more convincing than, "Hey guys! I saw a flash of light from space!" And if you're feeling generous, we'd love it if you'd share your images with us. See contact information below.

Definition of Acronyms and Links to More Information: Image of lidar pulse captured by Gregg Hendry of Ball Aerospace https://www.nasa.gov/larc/calipso-laser-flashhttps://www.facebook.com/nasalarc/photos/a.115596668486660.6213.115589531820707/823964850983168/ CNES: Centre National d'Études Spatiales (the French government space agency) ESA: European Space Agency Heavens Above website for finding satellite trajectories: http://www.heavens-above.com/Satellites.aspx CALIPSO: Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation. CALIPSO website: https://www-calipso.larc.nasa.gov/ CATS: Cloud-Aerosol Transport System (onboard the International Space Station, ISS) CATS website: https://cats.gsfc.nasa.gov/ ALADIN: Atmospheric LAser Doppler INstrument. Planned launch on the ESA's ADM (Atmospheric Dynamics Mission) Aeolus satellite in late 2017. ALADIN website: http://www.esa.int/Our_Activities/Observing_the_Earth/The_Living_Planet_Programme/Earth_Explorers/ADM-Aeolus/Payload GLAS: Geoscience Laser Altimeter System. GLAS was aboard ICESat (Ice, Cloud, and land Elevation Satellite), which launched in 2003 and rentered Earth's atmosphere in 2010. GLAS website: https://attic.gsfc.nasa.gov/glas/

13. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2016 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

14. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

For an application form contact the Executive Secretary This email address is being protected from spambots. You need JavaScript enabled to view it., Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

15. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants May be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 May 2017. There will be a secondary round of applications later in the year. Full details are set down in the RASNZ By-Laws, Section J.

For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it. Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

16. Quotes

"Some are born great, some achieve greatness, and some hire public relations officers." -- Daniel Boorstin.

"If God had intended us to fly he would have made it easier to get to the airport.? - Jonathan Winters

"That which has always been accepted by everyone, everywhere, is almost certain to be false." -- Paul Valery.

"You can?t have everything?where would you put it?" ?- Steven Wright.

"Much of the social history of the Western world over the past three decades has involved replacing what worked with what sounded good. -- Thomas Sowell.

"After one look at this planet any visitor from outer space would say 'I want to see the manager'" -- William S. Burroughs.

"I think the world is run by 'C' students." -- Al McGuire.

"The world is a tragedy to those who feel, but a comedy to those who think." -- Horace Walpole.

"To err is human -- and to blame it on a computer even more so." -- Robert Orben.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
P.O. Box 57 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand

 

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RASNZ Electronic Newsletter March 2017

The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy. The latest issue is below.

Email Newsletter Number 195

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Auckland Observatory's 50 Year Anniversary
2. 2017 Conference - Call for Papers
3. The Solar System in April
4. New Comet Lovejoy
5. Variable Star News
6. TRAPPIST-1's Planets
7. TRAPPIST-1's Radiation Deadly to Its Planets?
8. Audible Meteors Explained?
9. "The Space Between Us"
10. How to Join the RASNZ
11. Kingdon-Tomlinson Fund
12. Newsletter Format
13. Quotes

1. Auckland Observatory's 50 Year Anniversary

The Auckland Astronomical Society?s Observatory was opened on 21 March 1967 at the time of great interest in astronomy arising from the moon landing programme. Stardome will be playing a short birthday presentation as part of its 7:00 pm shows (Wed - Sun) for the last two weeks of March. Also the exhibit area has been revamped, with new displays on historic and forthcoming comments on space exploration.

-- From an article by Sarah Ell (stardome.org.nz) in the NZ Herald Weekend Supplement (11 March 2017, p. 8), passed along by Alan Baldwin.

2. 2017 Conference - Call for Papers

RASNZ Conference paper submissions

As you will know, the next conference of the Royal Astronomical Society of New Zealand (RASNZ) will be held in Dunedin over the weekend of 12th -14th May 2017.

There is still space left in the programme for talks and posters. The link to the paper submission form can be found on the RASNZ Conference website www.rasnz.org.nz/Conference or you can email titles/abstracts to me directly at This email address is being protected from spambots. You need JavaScript enabled to view it.. We will continue to accept papers until such time as the programme is full. Please note that you must be registered for the conference to give an oral presentation and papers will be lightly reviewed for suitability before being accepted. Once reviewed, papers will be accepted on a first come first served basis until the programme is full. A full list of accepted titles and abstracts is being maintained on the RASNZ Conference website.

TTSO11 paper submissions

Following the conference, the 11th Trans-Tasman Symposium on Occultations (TTSO11) will be held at the conference venue on Monday/Tuesday 15th - 16th May. Details of the registration for TTSO11 are available with the registration form for the conference, and paper submissions should be sent directly to the convenor Murray Forbes (This email address is being protected from spambots. You need JavaScript enabled to view it.). Note that this workshop will only be held if there is sufficient interest, so please register as soon as you can. We look forward to receiving your submissions and seeing you at the conference. Please feel free to forward this message to anyone who May find it of interest.

-- Warwick Kissling, RASNZ Standing Conference Committee.

3. The Solar System in April

NZ reverts to NZST (UT +12 hours) on April 2 at 3am. Consequently dates and times shown are NZST apart for any on April 1.

Sunrise, sunset and twilight times in April

        Times are for Wellington.  They will vary by a few minutes elsewhere in 
NZ.
                  April  1  NZDT                 April 30  NZST
                  morning  evening               morning  evening
       SUN: rise: 7.33am,  set: 7.15pm     rise: 7.04am, set:  5.31pm
Twilights
Civil:    starts: 7.09am, ends: 7.40pm   starts: 6.38am, ends: 5.58pm
Nautical: starts: 6.37am, ends: 8.12pm   starts: 6.05am, ends: 6.30pm
Astro:    starts: 6.04am, ends: 8.44pm   starts: 5.33am, ends: 7.02pm

April PHASES OF THE MOON (times NZST, as shown by GUIDE)

          First quarter: April  4 at  6.40 am (Apr  3,  6:40 UT)
  Full moon:     April 11 at  6.08 pm (06:08 UT)
  Last quarter   April 19 at  4.07 pm (04:07 UT)
  New moon:      April 27 at 12.16 am (Apr 26, 12:16 UT)

The planets in April 2017

Jupiter becomes visible all night so is a brilliant object in the evening sky. Saturn will be to the east by late evening. Mars will be low to the west after sunset setting before the end of astronomical twilight. Venus moves up in the morning sky during April, a brilliant object to the east. Mercury is too close to the Sun to observe all month.

MERCURY is virtually unobservable throughout April. It is at inferior conjunction between Earth and Sun at 5pm on the 20th. At conjunction the planet will pass 1.5° north of the Sun as "seen" from the Earth. Mercury will be 86 million km from the Earth and 64.4 million km from the Sun.

On the 1st Mercury, in the evening sky, will set only 30 minutes after the Sun. On the 30th, in the morning sky, it rises about 80 minutes before the Sun but at magnitude 2.6 is not likely to be visible due to twilight.

VENUS is a morning object in April. On the 1st it will rise some 45 minutes before the Sun, by the 30th it will rise more than 3 hours earlier than the Sun.

The planet will not be readily visible on April 1 when it is only 12° from the Sun. Its distance from the Sun increases steadily throughout April, particularly early in the month as Venus moves to the west through the stars, away from the easterly moving Sun. This will make it an easy object within a few days. It will be visible a little to the north of east at first shortly before sunrise.

Venus is in Pisces all month and is stationary on April 13 after which it will start moving to the east but less rapidly than the Sun. The position of the planet relative to the stars will change little during the month

The morning of the 24th will find the crescent moon some 4.5° to the upper right of Venus

MARS will remain a low early evening object during April. On the 1st it sets just over 80 minutes after the Sun, dropping only slightly to 75 minutes later on the 30th. It will be low, with a magnitude 1.5, visible only briefly as the sky darkens following sunset. Mars will set a little before the end of Astronomical twilight so not be an easy object.

During April, the planet moves to the east through Aries and on into Taurus on the 12th. On the 21st and 22nd it will be 3.5° above the Pleiades, by the end of April Mars will be 7° below the similarly coloured star Aldebaran. On the 28th the moon, a very thin crescent less than 5% lit, will be 5° to the upper left of Mars.

JUPITER is at opposition on April 8, NZ time. At opposition Jupiter will be 4.5 AU, 666 million km from the Earth and a further 150 million km from the Sun. The planet will be in Virgo moving in a retrograde sense to the west as the Earth overtakes it. Jupiter starts the month just over 6° from Spica, its slow westerly motion taking it to nearly 9.5° from the star on the 30th.

The full moon will be 6.5° from Jupiter on the evening of April 11, the moon at the apex of an inverted triangle formed by it, Jupiter and Spica.

SATURN will rise close to 11 pm NZDT 1st of April, which becomes 10pm NZST on the 3rd with the time of rise advancing to just after 8 pm by the 30th. Thus it becomes a prominent later evening object to the east at magnitude 0.3 to the east during the month. It will, of course, be readily visible in the morning sky. By the end of April Saturn will be highest and due north about 3.40 am.

Saturn is stationary on the 6th, after which it will start moving to the west, but its position in Sagittarius will change little throughout the month.

The 75% lit waning moon will be 3.5° to the lower right of Saturn on the morning of April 17, with the two closest at about 6 am.

Outer Planets

URANUS is at conjunction with the Sun on April 14. Hence it will be too close to the Sun to observe throughout April.

NEPTUNE, in the morning sky, rises about two and a half hours before the Sun on the 1st and nearly 5 hours earlier on the 30th. The planet is in Aquarius at magnitude 8.

PLUTO, magnitude 14.4, is in the morning sky rising about 12.40 am, NZDT, on the 1st and 9.45 pm on the 30th. It will remain in Sagittarius just under 2.5° from the 2.9 magnitude star pi Sgr.

Minor Planets

(1) CERES is an early evening object, brightening slightly from magnitude 9.1 to 8.9 during the month. It is quite close to Mars moving on a path almost parallel to the major planet which overtakes Ceres during the month. On the 1st they are 4° apart with Ceres above Mars. On the 8th they are at their closest, 3° apart. By the 30th Ceres is will be dropping behind Mars, the two then being 5° apart.

On the 12th both Ceres and Mars move from Aries to Taurus, with Ceres crossing the border shortly before Mars.

(4) VESTA, an evening object in April, is in Gemini. It passes Pollux, magnitude 1.2, early in April, the two being closest on April 7, just over 2° apart. The asteroid moves on into Cancer on the 24th. Vesta dims slightly during the month from magnitude 7.7 to 8.0. It sets about 12.45 am, NZDT, on the 1st and just before 10.30 pm, NZST, on the 30th.

-- Brian Loader

4. New Comet Lovejoy

Terry Lovejoy of Brisbane found another comet -- his sixth! -- on March 10. His posting to the Comet Watch Facebook group follows:

"Thank you everyone for your kind words, and of course to the people that sacrifice their spare time to get out there and do follow up observations on new comets like this.

The latest comet, C/2017 E4, was found on a set of 3 images made on the morning of March 10 (Local time) in the constellation of Sagittarius. Although my 6th discovery, this was the first discovery with the Hyperstar 14" Celestron Schmidt Cassegrain telescope. However, because the field of view is now smaller I must now make shorter exposures, and more of them, to cover similar amounts of sky as possible. However, I felt the extra aperture have has more than compensated especially since my location experiences quite bad light pollution being just 18 km from the centre of Brisbane, a city of more than 2 million people.

Back to the comet, it was found using MOD (Moving Object Detection) a computer program I wrote that searches sets of images for moving objects like comets of asteroids. I tend to run MOD with very high sensitivity, which means it will identify anything remotely resembling a moving object, resulting in mostly false positive detection's. In fact in crowded star-fields this can be as high as 90% false positives and so I must examine each detection manually. Nevertheless, this is huge time saver compared to examining the entire image manually. That morning a lot of the fields were in the milky way I had a large number of false detection's I had to examine, and there were also at least a dozen asteroids, but finally there was one object that had a definite coma and I knew almost certainly a comet. I then did some checks against known asteroids/comets plus some checks to eliminate internal optical reflections as a cause for the detection. This all checked out so I was certain of a new comet at this point.

I then sought independent confirmation from another observer, and looking at Messenger I could see Cristavao Jacques in Brazil was online, so I contacted him, but unfortunately dawn had started and he had closed up the observatory so there was no luck there. I then contacted Michael Mattiazzo and he was able to get a confirmation image not long after from a remote telescope in New Mexico. This was all well within the 24 hours of the actual discovery images, which is probably a record for me! The comet was then posted on the Possible Comet Confirmation Page and astrometry started to stream in over the next few days and within 3 days the orbit was known with enough certainty for it to be designated as C/2017 E4. The orbit indicates - unfortunately - this is an intrinsically small comet that probably stay quite faint (and it could even disappear altogether) but we can always hope for a better display."

---------- C/2017 E4 (Lovejoy) is in the morning sky, moving north-east, so getting closer to the sun. On March 20 it will be 108 million km from Earth and 138 million km from the Sun. It will be closest to the Earth, 91 million km away, on March 31. It passes 74 million km from the Sun on April 23. -- Ed.

5. Variable Star News

AAVSO Announcements ---------- The American Association of Variable Star Observers Annual Report for 2015-2016 has been released online. It is available at https://www.aavso.org/annual-report in both a high-resolution and a low-resolution version. There is useful information on AAVSO programmes contained within this document.

Stella Kafka, AAVSO director, has announced that Dr Bert Pablo will be joining the AAVSO as the new Staff Astronomer. He will start in July. Bert received his Astronomy PhD from Iowa State University, and then joined the BRITE-Constellation collaboration at the University of Montreal. His research has been on ?Heartbeat stars?. (Refer article on Iota Orionis below). You can find more information about Bert at: https://www.aavso.org/bert-pablo

This information was taken from the AAVSO (monthly) Communication ? March 2017.

Eclipsing Binary Stars ----------

Iota Orionis and the BRITE Constellation Project

Iota Orionis is a binary star system and is easily visible with the naked eye, being the brightest star in Orion?s sword in the constellation of Orion. The light from Iota Orionis is relatively stable 90 per cent of the time, but then dips rapidly followed by a large spike; a repeating one-per-cent spike in the light. Stars with this type of variation have been labelled Heartbeat stars due to the similarity of the variation to electrocardiogram rhythms. This unusual variation is the result of the interaction of two stars in a highly elliptical 30-day orbit around each other. The observations were made using the world?s smallest astronomical space satellites, referred to as ?nanosats?; there are five being used in the BRITE (BRIght Target Explorer)-Constellation program.

Iota Orionis represents the first time this effect has been seen in such a massive system (35 times the mass of the Sun), an order of magnitude larger than any in previously known systems, and the binary system allows for direct determination of the masses and radii of the components. On close approach gravitational forces distort the shape of the stars and trigger quakes in the star, allowing us to probe the star?s inner workings, just as we do for the Earth?s interior during Earthquakes. The phenomenon of quakes is very rare in massive stars in general and this is the first time induced quakes have ever been seen in a star this massive.

-- Abstracted from an AAVSO web-site News Article. For further information on BRITE go to http://www.brite-constellation.at/. An article on Iota Orionis was published in Monthly Notices of the Royal Astronomical Society, (Oxford University Press), http://doi.org/10.1093/mnras/stx207 February 9, 2017.

Analysis of Binary Stars ----------

One of the major projects of Variable Stars South since its inception has been the monitoring of binary stars visible in the Southern hemisphere, analysis of the light curves and deduction of the unique properties of the individual star systems. The light curves of binaries can be used to deduce the orbital elements, relative sizes and other properties of the stars in the system.

In the Variable Stars South Newsletters (website Tab Community, Heading Newsletters) Tom Richards has been writing about techniques for dong initial analysis and giving tips on things to watch out for in fitting models. The first article appeared in the 2016-3 (July) issue. (pp 24 ? 27) Reading the clues in light curves of eclipsing binaries Part I ? Finding star sizes. The subsequent article, Part II ? Interpreting eclipse depths appeared in the 2016 October issue. The articles use bold, clear diagrams to illustrate the systems.

?The techniques reveal how eclipse widths in light curves can tell us if the stars are close or well separated. We saw that relative depths tell us relative brightnesses and absolute depths give us strong clues about how complete the partial eclipses are. In the case of total eclipses, we saw further that we can derive the relative luminosities from the relative depths, and hence by combining luminosity and brightness, get the relative radii. We derived all those features of the eclipsing system by thinking qualitatively about the geometry?.

This information can be derived by logical reasoning and very simple arithmetic. Getting such results is an invaluable check on any astrophysical modelling you might go on to perform

The third in the series of articles, Part III ? The strange case of V477 Lyrae, was in the recently issued 2017 January issue. This star has an unusual light curve (the volcano shape) and the article shows an application of analysis to a complex, late evolutionary, system. The binary V477 Lyrae exists in a planetary nebula and is thus a star that has suffered mass loss to the planetary nebula, as well as mass being transferred from the secondary star to the primary.

The next article in the series will discuss investigating the colours and temperatures of the component stars.

-- Alan Baldwin

6. TRAPPIST-1's Planets

The star TRAPPIST-1 is an unassuming, M8 red dwarf star. It lies 39 light-years away in the constellation Aquarius. With a diameter only one-tenth that of our star, the dwarf puts out less than a thousandth as much light as the Sun.

Last year, Michaël Gillon (University of Liège, Belgium) and colleagues announced that a trio of small exoplanets orbits this small star (although the third world was of dubious reality). Now, after an intensive follow-up campaign, the team has discovered that there are actually seven planets, not three. All are likely rocky. Three lie in TRAPPIST-1?s putative habitable zone ? the region where, given an Earth-like composition, liquid water could be stable on the surface. But all, with enough hand-waving, might have a chance at liquid water.

The astronomers detected the exoplanets using the transit technique, which catches the tiny dip in starlight when a planet passes in front of its host star from our perspective. The discovery sequence began when the team found that what it had thought was a combined transit of planets #2 and #3 was in fact the crossing of three planets. The observers next studied TRAPPIST-1 with an impressive array of ground-based observations. But the big breakthrough came with the Spitzer Space Telescope which observed the star for 20 days. It saw 34 clear transits. The team was then able to combine their ground- and space-based observations to determine that the signals likely came from seven different planets.

Only six of those are firm detections, however. Number 7, or planet h, is iffy in its specs: The team only detected a single transit for it, and astronomers prefer to see three transits before calling something a candidate planet. Expect astronomers to haggle over this one in months ahead.

All of the seven exoplanets discovered around TRAPPIST-1 orbit much closer to their star than Mercury does to the Sun. But because TRAPPIST-1 is far fainter than the Sun, the worlds are exposed to similar levels of radiation as Venus, Earth, and Mars.

The orbital periods of the inner six planets range from 1.5 to 12 Earth days, with the period of outermost h being anywhere between 14 to 35 days. The smallest two worlds are about three-fourths as wide as Earth, the largest 10% wider. The biggest orbit is less than 20% as large as Mercury?s.

One of the wonderful things about this system is that the exoplanets? orbits are resonant with one another. This means that their orbital periods are rough integer multiples of one another. For example, in the same span of time that the innermost planet whips around the star eight times, the second planet takes five laps, the third three, and the fourth two. This setup gravitationally links the planets together and can lead to tiny shifts in their positions. Based on these shifts, the team could calculate the planets? gravitational influences on one another, and hence their approximate masses and densities. All are consistent with being rocky, the team concludes in the February 23rd Nature.

Such resonant orbits arise when worlds migrate from their original locations, Gillon explains. Astronomers think that when lightweight planets form far out in a star?s planet-forming gaseous disk, gas drag and such will make them advance inward. During this inbound migration, the worlds catch one another in resonant orbits, such that they can form a kind of ?chain of planets,? he says. In this case, the migration landed the exoplanets in what the team calls the ?temperate zone? ? orbits with enough incoming starlight that, with the right conditions, the planets might at least sometimes have liquid surface water. It?s a looser definition than that for ?habitable zone.?

The planets are also all likely tidally locked with their star, meaning they always point the same hemisphere at it, as the Moon does to Earth. So close to the star, the planets could experience huge tidal pulls, stretching and squeezing their interiors and spurring heating and even volcanism, similar to what we see on Jupiter?s Galilean moons.

TRAPPIST-1 is quiet for an M dwarf ? notably less active that Proxima Centauri, which also has a habitable-zone planet (although it?s likely a desert world). But unfortunately, astronomers don?t know how old the star is. It?s also unclear whether the planets? orbits are stable: The researchers haven?t determined the seventh planet?s orbit, nor do they know if there are other worlds in the system mucking things up. This kind of star, called an ultra-cool dwarf, is very common; roughly 15% of stars in the nearby galaxy fall into this category, Guillon estimates. Ultra-cool dwarfs live for trillions of years.

Read more about the result in the European Southern Observatory?s press release at https://www.eso.org/public/news/eso1706/

References: M. Gullion et al. ?Seven temperate terrestrial planets around the nearby ultracool drwarf star TRAPPIST-1.? Nature. February 23, 2017. Ignas Snellen. ?Earth?s Seven Sisters.? (editorial) Nature. February 23, 2017.

-- Abridged from an article by Camille M. Carlisle on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/dim-star-has-seven-earth-size-planets-2202201723/

7. TRAPPIST-1's Radiation Deadly to Its Planets?

The star with seven exoplanets puts out enough high-energy radiation to tear away the inner planets? atmospheres in a few billion years.

As part of the ongoing interest in this small sun, Vincent Bourrier (University of Geneva Observatory, Switzerland) and colleagues are putting together a picture of how much high-energy radiation streams out from the star, and what that radiation might mean for the planets.

The team used the Hubble Space Telescope to study the star?s ultraviolet output. Specifically, they looked at Lyman-alpha emission, which is a particular wavelength emitted by hydrogen atoms and comes from the star?s chromosphere, the layer between the stellar ?surface? (the photosphere) and the intensely hot, ionized, wispy corona. The team found that TRAPPIST-1 emits less than half as much Lyman-alpha radiation as other cool, exoplanet-hosting M dwarfs ? including Proxima Centauri, which radiates six times more in ultraviolet as TRAPPIST-1 does. That?s to be expected, since TRAPPIST-1 is also cooler than the other M dwarfs are.

However, last year the team also found that TRAPPIST-1 emits about as much in X-rays as Proxima Centauri. These X-rays come from the stars? coronas. The ratio of X-rays to ultraviolet is interesting for a couple of reasons. First, X-ray and ultraviolet output decrease with time for these stars, but X-rays drop off much faster. The fact that TRAPPIST-1 emits roughly a third as much energy in Lyman-alpha as it does in X-ray suggests that the star is ?relatively young,? the team posits in their March 2017 Astronomy & Astrophysics article.

What ?relatively young? means is an open question. Astronomers know the star is at least 500 million years old, because it has ?settled? into being an adult star. Beyond that, it?s anyone?s guess. Jeffrey Linsky (University of Colorado, Boulder), who has worked extensively on M dwarfs and the trends in Lyman-alpha and X-ray emission for different types of stars, says that TRAPPIST-1 seems both old and young. Stars are born spinning quickly, then slow as they age. TRAPPIST-1 rotates in 1½ days, which at face value would point to it being young, he says ? but astronomers don?t know how fast these ultra-cool dwarfs spin down. Furthermore, the star?s fast motion through space usually would indicate it?s a member of the old stellar population that comprises the galaxy?s halo, but that May be a fluke.

Bourrier agrees that the age question is currently unanswerable. The ratio of X-ray to ultraviolet emission seems to indicate that TRAPPIST- 1 is ?not extremely old,? he says, ?but I do not think that at this point we can say much more than this.?

The second reason the X-ray and ultraviolet levels matter is for habitability, a possibility which has received perhaps more attention than it deserves. Although the ultraviolet level is low, the radiation overall is still high enough that it could strip an Earth-like atmosphere from the inner two planets, b and c, in 1 to 3 billion years; for the planets d, e, f, and g (e, f, and g are in the putative habitable zone), the process would take anywhere from 5 to 22 billion years. The team does see a hint of atmospheric escape from b and c, although the slight drop in starlight that implies it might instead be due to coronal variability.

Reference: V. Bourrier et al. ?Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman-alpha line.? Astronomy & Astrophysics. March 2017.

-- Abridged from an article by Camille M. Carlisle on Sky & Telescope's website at http://www.skyandtelescope.com/astronomy-news/seven-planet-star-ageless-maybe-deadly-0603201723/

8. Audible Meteors Explained?

The astronomical literature is dotted with reports of observers hearing bright meteors that seem to hiss, pop, or ping. Now, a recent study in Nature: Scientific Reports out of Sandia National Laboratories suggests a possible cause.

Most of the meteors you see at night are tiny dust grains, burning up as they streak through Earth's upper atmosphere at speeds up to 70 km/s. Once in a great while, something really big, say, golf-ball-size or larger comes in, burning up in a brilliant fireball display. (A fireball is a meteor brighter than ?4 magnitude (as bright as Venus), and a bolide is a fireball with a bright terminal flash at the end of its trail.

Sometimes observers report hearing a distinct hiss or crackle accompanying many bright fireballs simultaneously with the bright flash. But the trouble with hearing concurrent sounds with meteors has always been the distance involved. Not only do meteors occur in the tenuous upper atmosphere, which is a poor propagator of sound, but they're also distant, occurring in the mesosphere about 75 to 100 km up. Think of lightning: how you always see the flash several seconds before the booming thunder arrives.

And yet reports of audible meteors persist. The Sandia study proposes that strong millisecond-long flashes recorded in bright fireballs are intense enough to induce radiative heating in dielectric materials such as dry leaves, clothing, or even hair in the vicinity of the observer, via what's called the photoacoustic effect. The irradiated surfaces heat the air next to them, producing tiny pressure oscillations ? in other words, sound. The study shows that a bolide around ?12 in magnitude (about half as bright as a full Moon) can induce an audible sound in dielectric material of around 25 decibels, loud enough to be heard. For context, a whisper is 10 to 20 decibels, on the lower threshold of what is barely audible. The study even suggests frizzy hair might be an even more effective transducer of the photoacoustic effect.

"It seems significant that people with frizzy hair are reported to be more likely to hear concurrent sound from meteors," the study notes. "Intuitively, frizzy hair should be a good transducer for two reasons. Hair near the ears will create localized sound pressure, so it is likely to be heard. Also, hair has a large surface-to-volume ratio, which maximizes sound creation.

The study notes that strong millisecond flashes were seen in virtually all of the bright bolide meteors documented by the Czech Fireball Network. One particularly brilliant ?15-magnitude fireball named EN091214 was recorded by the network in the early evening of December 9, 2014. Careful analysis of its rapidly changing intensity showed brief flares occurring dozens of times per second, and several witnesses in the vicinity heard sound at the same time. Calculations in the study suggest that the fireball's intense, rapidly varying light should have produced a sound level of 27 ± 3 decibels, consistent with ear-witness accounts.

Over the years, audible meteors have been explained as simply a psychological phenomenon, or perhaps a locally produced effect set up by low-frequency waves and a phenomenon known as electrophonic sound. Edmond Halley collected eyewitness accounts of a bright fireball seen over England on the night of March 19, 1718, which many witnessed claimed ?hiss(ed) as it went along, as if it had been very near at hand,? a claim dismissed by Halley himself.

-- Adapted from an article by David Dickinson on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-blogs/astronomy-space-david-dickinson/new-take-on-audible-meteor-mystery/

9. "The Space Between Us"

Jim Scotti posted the following critique/review on Facebook:

So we saw the movie "The Space Between Us" last night and while I enjoyed the film, it's clear that the director and writer weren't paying attention in their "Rocket Science" class. Here are a few issues (I don't think there are any real spoilers here). I didn't recognize a single star field. We apparently have developed subspace radio providing instant communication between Mars and Earth. As the spaceship approaches Earth (or Mars for that matter) the rocket engines are firing in the direction pushing toward the planet instead of pushing away from the planet to decelerate into orbit around the planet. You could see lots of stars when panning across a scene with daytime sunlit Earth or Mars in the scene. The Dream Chaser spacecraft can take off from a runway without a huge rocket to boost it and fire its rockets to achieve orbit (or at least to go suborbital for getting zero-G for a long time). We apparently need an SLS rocket to launch a 6 person crew into low Earth orbit on a Red Dragon spacecraft to rendezvous with our Mars transport spacecraft. While rocket engines are firing during the journey to/from Mars, the crew enjoys zero-G while floating around the cabin. And the trip to/from Mars still takes 7 months despite the continuous rocket firing. Did I mention that I enjoyed the movie in spite of the science flaws?

10. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2016 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

11. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants May be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 May 2017. There will be a secondary round of applications later in the year. Full details are set down in the RASNZ By-Laws, Section J.

For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it. Nichola van der Aa, 32A Louvain Street, Whakatane 3120.

12. Newsletter Format

Distribution of the past three Newsletters has been via MailChimp. This allows readers to unsubscribe automatically, a legislative requirement.

This issue is being sent in HTML format. That allows reading on any computer or mobile device. Comments on the usefulness, or otherwise, of this change are welcomed. -- Ed.

13. Quotes

"Okay - Other than giving us cars, planes, spaceships, cell phones, the internet, life-saving medicine, a dramatically increased life span, valuable warnings and guidance, a fundamental understanding of how our world works and Jurassic Park - what has science done for us?" -- https://www.facebook.com/EndTheWoo/photos/

"Life is like a roll of toilet paper; the closer you get to the end of the roll, the faster it goes." -- Anon. Quoted in The Economist letters, March 4, 2017, p. 12.

Newsletter editor:

Alan Gilmore Phone: 03 680 6817
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Lake Tekapo 7945
New Zealand