First: thank you for registering on the RASNZ web site. For RASNZ members this is the first step toward gaining access to the RASNZ Members only area of the site. The next step is that the site administrators will notice your registration and add you to the Members group - as a RASNZ member you don't need to do anything more. This will usually happen within a day, but may occasionally take longer if our membership officer is not available. If the process is taking too long and you are anxious to get access to Southern Stars please This email address is being protected from spambots. You need JavaScript enabled to view it. who will get it sorted for you pending confirmation by the membership officer.

If you aren't yet a member of RASNZ we don't yet offer much "extra" on the site, although we are thinking about what we can provide for you. If you have ideas about what you would like to see please This email address is being protected from spambots. You need JavaScript enabled to view it. and we'll see what we can do for you. Otherwise you might consider joining the society. See Glen Rowe's article outlining the benefits of membership.

Anyway, have a fun, inspiring and educational time visiting our site and please let us know what you like or would like to see improved.

Welcome to the Royal Astronomical Society of New Zealand website.

The RASNZ website provides astronomical information with a New Zealand and Southern Hemisphere focus for members of the RASNZ and for people interested in astronomy and astronomical events generally.

Registered RASNZ members have access to the online version of the Southern Stars (RASNZ journal) and other member specific information.

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Please take the time to create an account, especially if you are a RASNZ member.  For RASNZ members this opens up a members only section of the website where you can download the latest Southern Stars journal. We also provide various RASNZ documents for member's use. If you think there is something missing that we should provide to members please This email address is being protected from spambots. You need JavaScript enabled to view it. and let us know!

If you are not a RASNZ member now would be a good time to sign up for membership. You can do this using the online membership application form found under the RASNZ heading.

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Take some time to have a look around, and come back again soon as we develop and grow the site.

Clear Skies,
Peter J. & Simon L.

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

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

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
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