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.

Hey! How did I get here?

Some of the pages from our old site (from before 2014) haven't made it across to this site. Please This email address is being protected from spambots. You need JavaScript enabled to view it. and let us know which page you were looking for so we can provide it for you.

Please Register

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.

If you belong to a society affiliated with RASNZ note it during registration and we will keep you informed of upcoming events by email as information comes to hand.

We are here to help

Please do tell us (by emailing the This email address is being protected from spambots. You need JavaScript enabled to view it.) about any issues or missing material you notice. We would also love to hear about ideas for content you may have.

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 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

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 February 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 194

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. 2017 Conference - Call for Papers
2. The Solar System in March
3. Variable Star News
4. Fast Radio Burst Source Identified
5. Conflicting Measures of the Hubble Constant?
6. The Ancient Star That Faked Its Age
7. Micrometeoroids in the Gutter
8. Space May Wreak Havoc on Your Body
9. Auroral Stamp and Coin Issue
10. How to Join the RASNZ
11. Gifford-Eiby Lecture Fund
12. Kingdon-Tomlinson Fund
13. Quotes

1. 2017 Conference - Call for Papers

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 RASNZ standing conference committee (SCC) invites and encourages anyone interested in New Zealand Astronomy to submit oral or poster papers, with titles and abstracts due by 1st April 2017 or at such time as the SCC deems the conference programme to be full. 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.. 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.

-- Warwick Kissling, RASNZ Standing Conference Committee.

2. The Solar System in March

Dates and times shown are NZDT (UT + 13 hours).

Sunrise, sunset and twilight times in march

        Times are for Wellington.  They will vary by a few minutes elsewhere in 
NZ.
                  March  1  NZDT                 March 31  NZDT
                  morning  evening               morning  evening
       SUN: rise: 6.59am,  set: 8.06pm     rise: 7.32am,  set: 7.16pm
Twilights
Civil:    starts: 6.33am, ends: 8.32pm   starts: 7.07am, ends: 7.42pm
Nautical: starts: 6.00am, ends: 9.06pm   starts: 6.35am, ends: 8.14pm
Astro:    starts: 5.24am, ends: 9.41pm   starts: 6.03am, ends: 8.46pm

The southern autumnal equinox is on March 20 at 11:29 pm

March PHASES OF THE MOON (times as shown by GUIDE)

          First quarter: March  6 at 12.32 am (Mar  5, 11:32 UT)
  Full moon:     March 13 at  3.54 am (Mar 12, 14:54 UT)
  Last quarter   March 21 at  4.58 am (Mar 20, 15:58 UT)
  New moon:      March 28 at  3.57 pm (02:57 UT)

The Planets in March 2017

Mercury, Venus and Neptune are all at conjunction with the Sun during March so will be too close to the Sun for observation much of the month. Mars will remain an early evening object rather low to the west at sunset. Jupiter will move up into the evening sky being a few days short of opposition at the end of the month. Saturn is mostly a morning object but will rise shortly before midnight by the end of March.

MERCURY is virtually unobservable throughout March. It is at superior conjunction on the far side of the Sun at midday on the 7th, NZ time. At conjunction the planet will pass 1.5° south of the Sun as seen from the Earth. Mercury will then be 204 million km (1.36 AU) from the Earth placing it 55.8 million km beyond the Sun

Before conjunction it is a morning object, but rises only 30 minutes before the Sun on the 1st. After conjunction Mercury becomes an evening object, but even by the 31st it will set only 30 minutes after the Sun.

Evening Planets, Venus, Mars and Jupiter

VENUS sets some 40 minutes after the Sun on March 1. It is a very low object, only 4° up, 15 minutes after sunset, 30° north of the position of the set Sun. The comet Encke at magnitude 5.2 will then be 9° to the left of Venus and slightly lower but too faint to observe.

The angular distance of Venus from the Sun steadily decreases during the month until the planet is at inferior conjunction late on the evening of March 25. At conjunction the planet will pass 8° north of the Sun as seen from the Earth. It will be 42 million km from us and 108 million from the Sun.

After conjunction Venus will move into the morning sky and rise about 35 minutes before the Sun on the 31st but will be too low for observation.

MARS will also be a low early evening object. On the 1st it will be about 10° up 40 minutes after sunset, at the time Venus sets. Mars will be a little to the right of the position of Venus. Uranus will be less than 2° to the left of Mars but at magnitude 5.9 a difficult binocular object in the twilit sky.

Mars manages to keep ahead of the Sun during March, it sets 100 minutes after the Sun on the 1st and 85 minutes after on the 31st. The magnitude of Mars dims from 1.3 to 1.5 during the month.

On the evening of March 2 the 16% lit crescent moon will be just over 6° from Mars, above and to the right of the planet. A rather similar meeting of Mars and the moon will occur on the 31st, with the moon then 13% lit.

JUPITER will be the planet of the evening sky during March, although on the 1st it will not rise until 90 minutes after the Sun sets. By the end of March it will be up only 16 minutes after the Sun goes down.

On the 1st it will be 10.30 pm before Jupiter is reasonably easy to see 9° up to the east with Spica 4° to the upper right of the planet. The two form a pair throughout March, by the 31st they will be 6° apart.

On the 14th, two days after full moon, the latter will be 6.5° to the left of Jupiter as seen late evening, by the following morning the two will just over 4° apart. The rotation of the sky will bring the moon below Jupiter with Spica above the planet. The three should make an interesting grouping throughout the night.

SATURN in the morning sky.

SATURN rises an hour after midnight on the 1st and close to 11 pm on the 31st. Thus it remains essentially a morning sky object. The planet is in Sagittarius but some distance from the brighter stars of the constellation.

The last quarter moon will be just over 4° from Saturn on the morning of 21st NZ time.

Outer Planets

URANUS, at magnitude 5.9, remains in Pisces throughout the month setting 95 minutes after the Sun on the 1st, but only 30 minutes later on the 31st. It starts the month a couple of degrees to the left of Mars, but the latter moves steadily away from Uranus during the month. Also on the 1st the 9% lit crescent moon will be 7° to the left of Uranus with Mars 2° on the opposite side of Uranus, the three forming an almost horizontal line. The following evening the moon will be to the upper right of Mars.

NEPTUNE is another planet at conjunction with the Sun in March, on the 2nd. After conjunction it will become a morning object, rising nearly 2.5 hours before the Sun on the 31st. The planet at magnitude 8.0 remains in Aquarius throughout March.

PLUTO is in the morning sky rising about 2.35 am on the 1st and 12.40 am on the 31st. It will remain in Sagittarius about 2.5° from the 2.9 mag star pi Sgr.

Minor Planets

(1) CERES is an early evening object, magnitude 9.1. It starts the month in Cetus but moves into Aries starting on the 3rd. By the 31st it will set about 9 pm and be 4.5° to the upper right of Mars with the crescent moon 5.5° to the upper right of Ceres, the three not quite in line.

(4) VESTA an evening object in March will fade from magnitude 7.2 to 7.6 during the month. It is stationary early in the month and will then move slowly to the east. The asteroid is in Gemini and will be only 2.4° from beta Gem, Pollux, magnitude 1.2 by the end of March.

A loose cluster of asteroids are bright enough to be seen in binoculars at the beginning of March. On the 1st they are probably best seen about 11pm when they will be between NNE and NE. The asteroids are (9) METIS, (14) IRENE and (29) AMPHITRITE in Leo and (15) EUNOMIA in Sextans. Irene, magnitude 9.1, is just under 7° to the lower left of Metis, 9.2, while Amphitrite, 9.2, is some 14° to the upper right of Metis. Eunomia, mag 9.4,is further away, 21° above Metis. Regulus, the brightest star in Leo, is near midway between Eunomia and Metis, a little closer to the latter. At 11 pm the star will be about 30° above the horizon.

All four asteroids fade during the month and are likely to be lost to binocular view by the 31st.

COMET P/Encke (2P) is in Pisces fairly close to Venus with a magnitude 5.5 on the 1st. But it will be too low in southern skies following sunset to observe.

-- Brian Loader

3. Variable Star News

L2 Puppis has previously been classified as a Semi-regular variable because of its somewhat erratic brightness and has been observed by visual observers for a number of years. Part 2 of a report on observations of this star has appeared In the recent Variable Stars South Newsletter, 2017 January (Part I was in the 2016 July issue). In an analysis of visual observations (1984 to 1999) the visual magnitude has declined dramatically whereas filter observations in B-V remained essentially the same. This often occurs with visual observations of red stars in which the wavelength of maximum radiation moves during the cycle. Some recent observations (2012 – 2015) demonstrate that while the period is a little irregular the period has remained in a band of 130 to 150 days.

Recently some investigations have been carried out with very large telescopes to reveal the structure of the star and the reasons for its unusual behaviour. Firstly images from the ESO Very Large Telescope (SPHERE/ZIMPOL) in Chile revealed a disc of dust which would explain large changes in visual brightness. Secondly follow-up observations at the Atacama Large Millimetre/submillimeter Array (ALMA) have shown a companion. With the current estimate of its mass at approximately 12 Jupiters it is now classified as a brown dwarf; further observations over a long time base of 2000 days are required to pick up transits. The mass of the primary is estimated to be 0.66 solar mass and if it originally started at one solar mass it has undergone significant loss of material. The star is now regarded as a low-amplitude Mira, and it May be on its way to eventually forming a planetary nebula.

It is helpful to see the physical nature of this system being unravelled. Continuing visual and instrumental observations are warranted as well as long base line observations to determine the orbital elements.

Bibliography Aline Homes, Pauline Loader, John Homes, Stan Walker, Andrew Pearce (2017). Changes in L2 Puppis reflected in historic data – Part 2. Variable Stars South Newsletter, 2017 January.

Another paper on L2 Puppis was published recently in Southern Stars. Stan Walker, Neil Butterworth, Terry Bohlsen, Giorgio di Scala, Peter Williams (2016). The multiple periods of L2 Puppis. Southern Stars, December 2016, pp 5 -10.

-- Alan Baldwin.

4. Fast Radio Burst Source Identified

For the first time, a team of astronomers has determined the position of a fast radio burst in the sky and in space.

The first of these puzzling events was announced in 2007, when Duncan Lorimer (West Virginia University) discovered one in archived data from the Parkes radio telescope in Australia. What made that burst (and all following bursts) truly spectacular was the fact that it was also smeared over a wide range of radio frequencies, with lower-frequency waves arriving later than their higher-frequency counterparts. This dispersion implied that the radio waves had travelled some 3 billion light-years to Earth, making the faraway source — whatever it was — unbelievably bright.

And if that really was the case, then these fast radio bursts might just be entirely new, previously undetected astronomical sources. That thought prompted more theoretical papers than the number of observed bursts.

In the decade since, astronomers have detected 18 additional fast radio bursts. It’s a small number when you consider that they might appear as often as 10,000 times per day. Although every one appears to be an extragalactic voyager, traversing great distances before reaching Earth, astronomers hadn’t been able to precisely pinpoint where these bursts are coming from — until now.

However, FRB 121102, an ultrabright, ultrabrief burst radio source first detected on 2 November 2012 has flared up several times, making it the only fast radio burst known to repeat.

One of the most popular explanations for fast radio bursts is that they’re one-off events, like collisions between neutron stars or collapsing supernovae. But when FRB 121102 was found to repeat that scenario was abandoned, at least for this source.

Those repetitions have helped astronomers finally tie the fast radio burst to its home galaxy. It’s a long-anticipated discovery that will help shed light on these enigmatic bursts.

Astronomers had speculated that the culprit might instead be some sort of powerful outburst from a rotating neutron star or perhaps a pulsar. The trouble is that the burst doesn’t appear to follow the periodic pattern that you would expect for an object that regularly rotates.

In order to better narrow down the burst’s source, astronomers needed to find out where it was, not just on the sky but in the universe. So the team used the Karl G. Jansky Very Large Array in New Mexico with the hope of catching another one of its outbursts in a larger scope. They were lucky enough to detect not one, but nine additional bursts, allowing them to localize it to within one-tenth of an arcsecond. That’s 18,000 times smaller than the diameter of the full Moon.

To improve the position the team then used the European Very Long Baseline Interferometer Network — an array of radio dishes spread across Europe — and Arecibo to further refine its location. That did the trick. Not only were they able to see that the bursts originated from a faint smudge (some 100 million times fainter than the faintest star you can see with your naked eye), but they also coincided with a persistent radio source at the same location.

Follow-up observations with the Gemini North Telescope on Mauna Kea, Hawaii, revealed that the smudge was actually a dwarf galaxy 2.5 billion light-years away.

This has allowed the first calculation of the intrinsic brightness of a fast radio burst. These affirm what many astronomers had suspected all along: these bursts are so bright they might push the boundaries of known physics. “Just for an instant, when this burst flashes, the luminosity of that burst outshines all the stars in its own galaxy by far,” said Sarah Burke-Spolaor (West Virginia University) at a meeting of the American Astronomical Society on January 4th. “It rivals the luminosity of an active galactic nuclei, which are formed from the power accreted onto a supermassive black hole.”

Although the nature of FRB 121102 remains unknown, hints can be gleaned from the fact that its host galaxy is a dwarf galaxy — disappointing news to those who argued for neutron stars. Because the galaxy doesn’t contain a high number of stars and because most of those stars seem relatively young, it likely doesn’t contain a high number of neutron stars, making this scenario less likely.

But if you’re looking for an intriguing culprit, don’t worry. Not only did the team pinpoint a host galaxy, but also a nearby persistent radio source within the galaxy. Although the exact relationship between the duo remains unclear, it’s likely that they’re somehow interacting. One scenario is that the persistent radio source is an active galactic nucleus that blows bubbles of plasma in space, which glow for a snapshot of time before they’re destroyed. That’s the fast radio burst. Since the galaxy will likely replenish those bubbles, this could happen again and again.

The authors are careful to point out that this is just speculation. The team plans to study the duo further with upcoming Hubble Space Telescope observations. In the meantime, they’re continuing to chase fast radio bursts with the hope that they’ll spot more repeating bursts and localize more in the coming years. “I would dare to say that every major astrophysical observatory is chasing this phenomenon,” said Burke-Spolaor.

Reference: S. Chatterjee et al. “A Direct Localization of a Fast Radio Burst and Its Host.” Nature, January 05, 2017.

-- Article by Shannon Hall on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/astronomers-trace-fast-radio-burst-to-a-surprising-source/

5. Conflicting Measures of the Hubble Constant?

By using galaxies as giant gravitational lenses, an international group of astronomers using the NASA/ESA Hubble Space Telescope have made an independent measurement of how fast the Universe is expanding. The newly measured expansion rate for the local Universe is consistent with earlier findings. These are, however, in intriguing disagreement with measurements of the early Universe. This hints at a fundamental problem at the very heart of our understanding of the cosmos.

The Hubble constant — the rate at which the Universe is expanding — is one of the fundamental quantities describing our Universe. A group of astronomers from the H0LiCOW collaboration, led by Sherry Suyu (Max Planck Institute for Astrophysics, the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan, and the Technical University of Munich), used the Hubble Space Telescope and other telescopes in space and on the ground to observe five galaxies in order to arrive at an independent measurement of the Hubble constant.

The new measurement is completely independent of — but in excellent agreement with — other measurements of the Hubble constant in the local Universe that used Cepheid variable stars and supernovae as points of reference.

However, the value measured by Suyu and her team, as well as those measured using Cepheids and supernovae, are different from the measurement made by the Planck satellite. But there is an important distinction — Planck measured the Hubble constant for the early Universe by observing the cosmic microwave background.

The H0LiCOW team determined a value for the Hubble constant of 71.9 ± 2.7 kilometres per second per Megaparsec. In 2016 scientists using Hubble measured a value of 73.24 ± 1.74 kilometres per second per Megaparsec. In 2015, the ESA Planck Satellite measured the constant with the highest precision so far and obtained a value of 66.93 ± 0.62 kilometres per second per Megaparsec. (A Megaparsec is 3.262 million light years.)

While the value for the Hubble constant determined by Planck fits with our current understanding of the cosmos, the values obtained by the different groups of astronomers for the local Universe are in disagreement with our accepted theoretical model of the Universe.

“The expansion rate of the Universe is now starting to be measured in different ways with such high precision that actual discrepancies May possibly point towards new physics beyond our current knowledge of the Universe,” elaborates Suyu.

See the full press release with images at http://www.spacetelescope.org/news/heic1702/

-- From the link passed along by Karen Pollard.

6. The Ancient Star That Faked Its Age

49 Librae, a relatively bright star in the southern sky, was until

recently believed to be 2.3 billion years old, or half as old as Earth’s Sun. Scientists have now proved this theory incorrect, finding that the star was in fact formed 12 billion years ago at the same time as the Milky Way. Researchers at the at Ruhr-Universität Bochum (RUB) led by Dr Klaus Fuhrmann and Professor Rolf Chini have now revealed the reason behind scientists’ decades-long assumption of the star’s age, publishing their study in the Astrophysical Journal.

Scientists determine the age of stars based on their chemical composition. Old stars that had been formed during an early stage of the universe do not contain any heavy elements; this is because those elements were generated later, following the nuclear fusion of many generations of stars. 49 Lib does contain heavy elements, which led researchers to believe that it was a relatively young celestial body. However, it was discovered in 2016 that 49 Lib is part of a dual star system, its partner being an almost extinguished star that is as good as invisible. At the end of its life, as the partner star expanded, its matter would have escaped into space and been attracted by the gravity of the neighbouring 39 Lib, which would have absorbed it. And what did that expelled matter include? Heavy elements, of course!

The RUB researchers were further able to determine the age of 49 Lib based on its spectra, breaking the light emitted by the star into its individual components and decoding the wavelength at which the star emits the most light. This method enabled the team to track the dual system’s entire evolution: they now know, for example, the masses with which the star’s life had begun and how those masses have evolved since then.

The researchers revealed that both 49 Lib and its partner would have initially had similar mass properties as the Sun. When 49 Lib took over the matter of its extinguishing partner, it gained a weight of approximately 0.55 solar masses. The more mass, the shorter the star’s lifespan. The weight gain has thus reduced 49 Lib’s lifespan dramatically, so that the star will soon become a red giant.

As a red giant, 49 Lib will no longer be able to keep its matter together, undergoing the same process that its partner underwent as it turned into a white dwarf. Furthermore, part of the matter of 49 Lib will be attracted by its extinguishing star partner, thus returning it from whence it came. “If that partner cannot rid itself of the matter in small eruptions, it will fully explode as a supernova,” explained Professor Chini.

Slightly abridged from the Labonline article at http://www.labonline.com.au/content/research-development/news/the-ancient-star-that-faked-its-age-1152020963

The Astrophysical Journal abstract is at http://iopscience.iop.org/article/10.3847/1538-4357/834/2/114/meta

-- From the link passed along by Tony Ellis.

7. Micrometeoroids in the Gutter

Do you dread having to clean out the rain gutters. Try rethinking what it is you're cleaning. Mixed in with the muck and debris May just be a few tiny micrometeorites, debris literally from out of this world. A recent study out of Imperial College London, the London Natural History Museum, the University of Brussels, and a group known as Project Stardust has confirmed that there is a silent cosmic rain of micrometeoroids.

Micrometeoriods are small dust particles slamming into Earth's atmosphere as our planet orbits the Sun at 30 km/sec. They are notoriously difficult to study in their pristine state, but Project Stardust has been collecting the sediment from urban rooftop gutters for the past seven years in a bid to find them. And they succeeded: the recent study recovered a fascinating array of micrometeorites from the urban rooftops of Oslow, Norway and Paris, France.

Finding tiny bits of space debris isn't easy. Project Stardust collected and filtered through 300 kg of material from a total collection area covering 30,000 square meters. Of these, about 500 rocks passed stringent scrutiny.

To pick out these tiny needles from the metaphorical haystack, scientists first sifted through the collected debris with magnets, since most ordinary chondrite-type meteorites have a high iron content. Next, the scientists washed the remainder and then painstakingly sorted the rocks by size and shape. Finally, the final suspects were examined under a binocular microscope, where researchers looked for the lustre and spherical shape indicative of ablation during atmospheric entry. Of the 500 particles collected, 48 were then embedded in resin and polished for further characterization.

The micrometeorites collected are tiny, most just 300 to 400 micron in size. The largest of them are just under half a millimetre across, barely visible to the naked eye.

The idea of “rain gutter micrometeorites” is a matter of minor controversy in meteorite-collecting circles. The idea became vogue thanks to a 1940 micrometeorite study by American meteoriticist Harvey Nininger. However, later studies found that the abundance of magnetic microspherules dropped sharply away from urban areas, and modern pollution is full of metallic particulates that add a steady stream of false-positive “micrometeor wrongs,” confounding search efforts. Still, it's a fun and easy project to fit a bucket's bottom with an NIB (neodymium-iron-beryllium) super-magnet, place the bucket under the end of a rain gutter, and see what turns up.

In this study, the team specifically looked for micrometeorites that matched the mineral compositions of known samples, including deep-sea samples, as well as those from the South Pole Water Well in Antarctica, which also contain similar tell-tale iron-nickel and sulphide beads indicative of micrometeorites.

In addition to being the largest study to date of rooftop material, this also marks the first long-term measurement of the flux of incoming micrometeoroid dust. The team estimates that 100 tons of micrometeorite dust falls over Earth every day, with about one micrometeroid “hit” per square meter per year. Samples taken from the South Pole Water Well, Larkman Nunatak moraine, and Cap Prud'homme in Antarctica also chronicle the steady flux of micrometeoroid bombardment over the past million years.

Antarctic studies also find a subtle change in the composition of relic material as well. The rooftop study isn't carried out over a long enough timescale to confirm this result, but it can give context. “[The new study] is the only sampling of verified micrometeorites from roof tops,” says Matthew Genge (Imperial College London). “Because these are the youngest large particles, it allows us to make comparisons with those collected over a much longer period.”

NASA is also interested in the flux of micrometeoroids through the near-Earth environment. Astronauts have chronicled impacts on the International Space Station, such as one that ripped through one of the station's solar arrays in 2013. Shuttle engineers would also routinely find pits from micrometeoroid impacts on the windows of orbiters back when the fleet was in service. Spalling caused by micrometeroid impacts on the space station's exterior is also a concern, as the sharp edges of these tiny pits seen on exterior handles could easily rip a spacesuit glove.

Despite the challenges inherent in collection and analysis, Project Stardust founder Jon Larsen continues to encourage amateur urban meteorite hunters on his Facebook page. "The holy grail of the research on micrometeorites," Larsen says, "will be to find a way to separate micrometeorites from terrestrial contamination."

See the paper abstract at http://geology.gsapubs.org/content/45/2/119.abstract

-- Abridged from an article by David Dickinson on Sky & Telescope's webpage at http://www.skyandtelescope.com/astronomy-news/new-study-hunts-for-rain-gutter-micrometeorites/

8. Space May Wreak Havoc on Your Body

Nothing in our lives is more pervasive than gravity. We can shield our senses from the effects of light, sound, or any other sort of input, but there is no way to shield ourselves from the downward tug of the Earth’s gravitational field. Our bodies evolved to function well in gravity; our bones support us, our muscles strain against it, even our organs sit in positions that respond to the pull of gravity. Venturing into space and away from the presence of gravity is not something that evolution prepared our bodies or our minds to do.

At first, people wondered if astronauts in space would be able to eat and digest food (they can), or if their blood would flow properly (it does, for the most part). That much was comforting; maybe this wouldn’t be so hard, after all.

But what happens in the long run? If humans are ever going to undertake significantly long journeys away from the Earth, we’d better be very clear about what impact living away from gravity, or in reduced gravity (like on the Moon or Mars) is going to have on our bodies.

Luckily for us, we have an absolutely amazing tool to learn more about how to live and work away from gravity: the International Space Station. It sort of boggles my mind that we’ve had people in space, continuously, for more than 16 years now. And last year, Scott Kelly and Mikhail Kornienko spent a year in space together — a year filled with every poke and prod and medical experiment they could do up there to try to nail down exactly what was happening to their bodies over time.

To make matters even more interesting, Mark Kelly, Scott’s twin and also an astronaut, stayed on the ground but volunteered to be subjected to the exact same experiments as a control sample. The data taken from these people will be invaluable in planning a journey to Mars, where astronauts will be required to make a journey of six months or more, then arrive strong, healthy, and ready to begin setting up habitats and begin exploring the red planet.

NASA anticipated some challenges: maintaining bone mass is a problem, and astronauts work out for hours every day to keep their muscles strong. But some things were unexpected, like degraded vision and a higher likelihood of kidney stones. Other issues seemed trivial at first, but they might wear down morale over long periods of time: how would you like to feel like you have the flu, or to not be able to taste your food for months on end?

So living and working in space isn’t so easy after all. Right now, we are honestly not sure how to get people all the way to Mars and keep them healthy. But it’s not time to get discouraged; it’s time to learn everything we can. We are getting better all the time at keeping our bodies working well in space, and we will be armed with that knowledge, someday, when we arrive on the surface of Mars. And above your head right now, careening around the Earth once every 90 minutes, is the laboratory filled with the amazing people that will get us there.

For links to the podcast by Michelle Thaller see http://www.skyandtelescope.com/astronomy-resources/orbital-path-astronomy-podcast/orbital-path-warning-space-wreak-havoc-human-body/

https://soundcloud.com/prx/you-had-me-at-pee-brittle---------- See 'Scientific American' February 2017, p.50-55, for more bad news for would-be interplanetary space travellers.

9. Auroral Stamp and Coin Issue

John Hearnshaw points out that NZ Post as a stamp issued featuring the Aurora Australis and Aoraki Mackenzie International Dark Sky Reserve with images recorded from Mt John. The details are at https://stamps.nzpost.co.nz/new-zealand/2017/southern-lights The set of six stamps was first issued on 8 Feb.

They have also issued a pricey 1oz silver proof coin that replicates the auroral effect with holography. The web link is the same as above.

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. 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.

12. 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.

13. Quotes

"xkcd.com is best viewed with Netscape Navigator 4.0 or below on a Pentium 3±1 emulated in Javascript on an Apple IIGS at a screen resolution of 1024x1. Please enable your ad blockers, disable high-heat drying, and remove your device from Airplane Mode and set it to Boat Mode. For security reasons, please leave caps lock on while browsing." -- Randall Munroe.

"You Matter -- unless you multiply yourself by the speed of light… then you energy." -- Blackboard sign posted on https://www.facebook.com/scienceteeshirts/ photos/

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