RASNZ Electronic Newsletter April 2016

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 184

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. RASNZ Conference Reminder
2. RASNZ Conference Auction
3. Astrophotography Workshop - May 23-24
4. RASNZ Astrophotography Competition
5. Notice of Annual General Meeting
6. Affiliated Societies' Committee Meeting
7. The Solar System in May
8. VSSS4 - A Successful Variable Star Event
9. Gamma Rays from Gravitational Wave Source?
10. No Gravity Waves from Galaxy Mergers - So Far
11. Two Nearby Supernovae in 'Recent' Times
12. Evidence of Exoplanetary System from 1917
13. Correction: Radio Interferometry's 70th Anniversary
14. How to Join the RASNZ
15. Gifford-Eiby Lecture Fund
16. Kingdon-Tomlinson Fund
17. Quote

1. RASNZ Conference Reminder

It is now only a month out from the RASNZ Conference, to be held May 20th-22nd in Napier. We encourage all RASNZ members (and their friends in local Societies) to come to the conference, which this year features Dr Michele Bannister, an ex-pat Kiwi and planetary astronomer. She will give an invited talk describing recent discoveries in the outer solar system and also a public talk on the Sunday afternoon describing recent discoveries at Pluto made by the New Horizons spacecraft. For those interested, the conference will be followed on May 23rd-24th by an astrophotography workshop.

We have now closed submissions for oral presentations as the programme is full, but there is still more space for poster papers. Details of the conference, with links to the registration and poster paper submission pages are to be found at http://www.rasnz.org.nz/ .

-- Warwick Kissling, RASNZ Standing Conference Committee.

2. RASNZ Conference Auction

It is planned to hold an auction of astronomical paraphernalia at the RASNZ conference banquet on 21 May. If any members of the Society have objects they would like to dispose of at the auction, could they please email the Society president, Prof John Hearnshaw (This email address is being protected from spambots. You need JavaScript enabled to view it.). The proceeds from the auction will all go to the Society, first to fund the prizes in the planned Astroquiz at the conference, and if there are surplus funds beyond that, they will be added to the Graham Blow fund that supports the competition `Students with a Passion for Astronomy´, whereby students are supported to come to the RASNZ conference.

The number of items to be auctioned will be limited to 2 or 3, and I will make a selection of the most interesting and tantalizing.

Those donating items should bring them to Napier; or, if that is not possible, then full details and photographs should accompany your email.

Please contact me by May 10 with your entries for the auction.

-- John Hearnshaw, President, RASNZ

3. Astrophotography Workshop - May 23-24

Immediately following the RASNZ conference on Monday 22nd and Tuesday 23rd (until lunchtime) there will be an astrophotography symposium. It will be at the Hawke´s Bay Holts Planetarium on the grounds of the Napier Boys´ High School, Chambers Street, Napier. This 1.5-day event will be an astrophotographer´s dream as a plethora of astronomical topics will be discussed covering everything from getting the images at the telescope through to processing the images at the computer. We are fortunate to have a range of top New Zealand astrophotographers presenting talks and speaking from personal experience.

We are especially pleased to announce that Rolf Olson, arguably the best astrophotographer in New Zealand, will be sharing from his vast array of image processing skills. Rolf recently achieved `best in show´ image in the Oceanside Photo and Telescope (OPT) annual imaging competition. Rolf is an expert in the astro-image processing software PixInsight. Rolf´s explanation of, and experience with, PixInsight will be the main thrust of the workshop. So come along and learn from one of the world´s best imagers! For more of Rolf´s incredible work go to http://www.rolfolsenastrophotography.com/ To register, go to the RASNZ conference registration page http://www.rasnz.org.nz/groups-news-events/conference-registration. If you have any queries regarding the workshop or would like to possibly present a talk, please contact me at This email address is being protected from spambots. You need JavaScript enabled to view it. Note that there is an additional $20 `late fee´ if paid after 20 April. Note that you don´t have to be a RASNZ member to attend.

-- John Drummond

4. RASNZ Astrophotography Competition

The RASNZ's Astrophotography Section's annual astrophotography competition is approaching. This year we are very fortunate to have Peter Ward from Australia as the judge. Peter is considered one of the top astrophotographers in Australia and produces lovely work. Peter is the owner/operator of Advanced Telescope Supplies - the website can be seen at http://www.atscope.com.au/ . Further information about Peter can be seen at http://www.mikesalway.com.au/the-top-10-best-astrophotographers-in-australia/ .

The deadline is 11pm Saturday 30th April 2016. Each person can enter two (2) entries in each of the four sections. The photos will be on electronic display at the RASNZ conference at Napier. Prizes and certificates go to the top three places (1-2-3) in each section! There are four sections: Deep Sky, Solar System, Picturesque, and Scientific. Images have to have been taken between 1st May 2015 and 30th April 2016. They can be sent to me at This email address is being protected from spambots. You need JavaScript enabled to view it. . Large Tiffs or Jpegs are fine (under 10 MB please).

Please note that the Scientific Section is undersubscribed, so put your scientific minds to work and come up with a photo (or two) that show some aspect of scientific curiosity and photo journalism. Keep snapping - you´ve got 12 imaging days (nights) left!

-- John Drummond.

5. Notice of Annual General Meeting

The 93rd Annual General Meeting of the Royal Astronomical Society of New Zealand will be held on Saturday 21 May 2016 at the Museum Theatre Gallery, Hawkes Bay. The meeting will begin at 4pm. Notices of motion are invited for the AGM and should reach the Secretary by 9 April 2016 to be included on the agenda.(This email address is being protected from spambots. You need JavaScript enabled to view it.) Items for the agenda include the Society´s Annual Report and the completion of the election of officers and council members. The nomination period for council has closed but there has been no nomination for secretary. Nominations can be accepted from the floor at the AGM. The minutes of the 2015 AGM are available on the RASNZ website. A full agenda for the AGM will be published after 9 April 2016.

-- Rory O´Keeffe, Secretary, RASNZ

6. Affiliated Societies' Committee Meeting

The Affiliated Societies Committee Meeting will be held on Friday 20 May 2016 at 4 pm. The venue is yet to be announced. Normally the meeting is attended by the President of Affiliated Societies or their nominated representative. Affiliated societies are invited to notify the secretary about their attendance and the names of the representatives who will be attending. The minutes of the previous meeting are available on the RASNZ website. The business of the meeting will include the election of the Affiliated Societies Representatives on the council of RASNZ. Any items affiliated societies would like to place on the agenda should be forwarded to the secretary at This email address is being protected from spambots. You need JavaScript enabled to view it..

-- Rory O´Keeffe, Secretary, RASNZ

7. The Solar System in May

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in may

                            May  1  NZST                   May 31  NZST
              morning        evening         morning        evening
SUN:         rise: 7.05am,  set: 5.29pm     rise: 7.33am,  set: 5.03pm 
Twilights
 Civil:    starts: 6.39am, ends: 5.56pm   starts: 7.05am, ends: 5.31pm
 Nautical: starts: 6.07am, ends: 6.29pm   starts: 6.31am, ends: 6.06pm
 Astro:    starts: 5.34am, ends: 7.01pm   starts: 5.58am, ends: 6.39pm

May phases of the moon (times as shown by guide)

          New moon:      May  7 at  7.30 am (May  6, 19:30 UT)
  First quarter: May 14 at  5.02 am (May 13, 17:02 UT)
  Full moon:     May 22 at  9.14 am (May 21, 21:14 UT)
  Last quarter   May 30 at 12.12 am (May 29, 12:12 UT)

The planets in May

Mercury is at inferior conjunction on May 9 when it will transit the Sun, an event visible from the opposite side of the Earth to NZ. After conjunction Mercury becomes a morning object and will be readily visible towards the end of May. Mars is at opposition on May 22 when it will be as bright as Jupiter. Mars will be close to Antares and Saturn.

MERCURY starts May as an evening object, but sets only 24 minutes after the Sun on the 1st, so is not observable. It is at inferior conjunction between the Earth and Sun on the morning of May 10 NZST.

At the May conjunction Mercury will transit the Sun. The transit starts at 11:12 pm on 9 May (NZST) and ending at 6:42 am on 10 May (NZST); UT date and times are May 9, 11:12:18 and 18:42:14 respectively. The end is about half an hour before sunrise at Wellington. Thus the transit is not visible from New Zealand nor from Australia. The Middle East, Europe and Africa are well placed for viewing the start of the transit, the later stages are visible from the Americas. Apart from much of the Atlantic Ocean, Greenland and Brazil are the best places for seeing the entire event.

After conjunction Mercury becomes a morning object moving away from the Sun fairly rapidly. By May 24 the planet, at magnitude 1.8 will be some 7.5° above the horizon an hour before sunrise. A week later Mercury, now magnitude 1.0, will be nearly 10° up an hour before sunrise. Look for Mercury in a direction about 25° north of east.

VENUS, in the morning sky, is close to the Sun all month. At the start of May its elongation is 10° with the planet rising 50 minutes before the Sun. By the 31st it will rise only 9 minutes before the Sun. So viewing will be difficult.

MARS, which has been steadily brightening recently, is at opposition on May 22. At magnitude -2.1 it will briefly be as bright as Jupiter. Mars will be close to Antares, the two just under 9° apart. The star at magnitude 1.1 is looking almost dim compared to the planet. Saturn will be about 12° from Mars and on the evening of May 22, the just past full moon will be 9° distant.

Mars is closest in its orbit to the Earth on May 31 when the two will be just over 75 million kilometres apart.

JUPITER will be best placed for viewing early evening, although it doesn´t set until after midnight. The planet is in Leo, its position changes little during the month, being stationary on May 10.

The 66% lit moon will be just over a degree from Jupiter on May 15.

SATURN rises an hour and three quarter after the Sun sets on May 1, and just 6 minutes after sunset on the 31st. So it is best viewed later evening. The planet, in Ophiuchus, is a few degrees from Antares. Saturn´s magnitude brightens from 0.2 to 0.0 during the month.

The moon passes Saturn on the 22nd but will be closest well after they set in NZ. The two are about 7° apart on the evening of May 22 and about 7.5° apart the following evening with the moon the opposite side of Saturn.

Outer planets

URANUS is a morning object in Pisces at magnitude 5.9. It rises about 100 minutes before the Sun on the 1st increasing to 4 hours earlier on the 31st.

NEPTUNE is in the morning sky, rising just after midnight by May 31. The planet, at magnitude 7.9 is in Aquarius. Neptune is moving to the east past the 3.7 magnitude star lambda Aqr. The two are closest mid month when less than half a degree apart. Neptune will be to the upper right of the star. No stars as bright as Neptune are between the two.

PLUTO at magnitude 14.4 rises close to 9.30 at the start of May and 2 hours earlier by the end of the month. The planet remains in Sagittarius less than 1° from the 2.9 magnitude star pi Sgr.

MINOR PLANETS (1) Ceres, magnitude 9.3, is in Cetus during May. It rises just before 4 am on the 1st and just over an hour earlier by the 31st.

(4) Vesta, magnitude 8.4, is in Taurus.  Its starts May as an evening 
object setting less than an hour after the Sun.  It is at conjunction 
with the Sun on the 24th when the two will appear about 3.5° apart.

(7) Iris is at opposition on May 29 with a magnitude 9.2. The asteroid will be in Ophiuchus, 3° from Antares, just under 6° from Saturn and 9.5° from Mars. The 5th magnitude star rho Oph will be just over 13 arc minutes from Iris. The star has two close companions easily visible in binoculars at magnitudes 6.8 and 7.3, each about 2.5 arc minutes from brighter star.

-- Brian Loader

8. VSSS4 - A Successful Variable Star Event

Variable Stars South's Fourth Symposium took place at the University of Sydney on Good Friday, 25 March 2016, and had just over 30 participants. It was preceded by an enjoyable evening at a local restaurant in a 'getting to meet one another' occasion.

The range of papers was impressive, emphasising the variety of research areas as shown in our annual report in Southern Stars. These comprised eleven presentations with five poster papers and were supplemented by a further eleven papers at the succeeding NACAA conference. An encouraging feature was several presentations by visual observers, with two more at the NACAA event.

Topics ranged from a variety of eclipsing binaries, through Mira, delta Scuti and Cepheid pulsating variables to L2 Puppis, a possible incipient planetary nebula. Techniques covered CCD and DSLR photometry, visual measures, through to video cameras and spectroscopy. These will begin appearing on our web site over the next month or two. In contrast to VSSS3 almost all the participants were active observers.

The whole event was enjoyable - perhaps the best conference I´ve ever attended. A good venue, good organisation and a wide range of papers - excellent in both content and presentation. I hope to see many of these in formal print shortly. It was announced that the next NACAA conference will be in Ballarat in 2018 and, whilst I will have retired as director by then and it will not be my decision, it sounds a useful venue for VSSS5.

-- Stan Walker

9. Gamma Rays from Gravitational Wave Source?

On September 14 waves of energy traveling for more than a billion years gently rattled space-time in the vicinity of Earth. The disturbance, produced by a pair of merging black holes, was captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana. This event marked the first-ever detection of gravitational waves and opens a new scientific window on how the universe works.

Less than half a second later, the Gamma-ray Burst Monitor (GBM) on NASA's Fermi Gamma-ray Space Telescope picked up a brief, weak burst of high-energy light consistent with the same part of the sky. Analysis of this burst suggests just a 0.2-percent chance of simply being random coincidence. Gamma-rays arising from a black hole merger would be a landmark finding because black holes are expected to merge "cleanly," without producing any sort of light.

"This is a tantalizing discovery with a low chance of being a false alarm, but before we can start rewriting the textbooks we´ll need to see more bursts associated with gravitational waves from black hole mergers," said Valerie Connaughton, a GBM team member at the National Space, Science and Technology Center in Huntsville, Alabama, and lead author of a paper on the burst now under review by The Astrophysical Journal.

Detecting light from a gravitational wave source will enable a much deeper understanding of the event. Fermi's GBM sees the entire sky that is not blocked by Earth. It is sensitive to X-rays and gamma rays with energies between 8000 and 40 million electron volts (eV). For comparison, the energy of visible light ranges between about 2 and 3 eV.

With its wide energy range and large field of view, the GBM is the premier instrument for detecting radiation from short gamma-ray bursts (GRBs), which last less than two seconds. They are widely thought to occur when orbiting compact objects, like neutron stars and black holes, spiral inward and crash together. These same systems also are suspected to be prime producers of gravitational waves.

"With just one joint event, gamma rays and gravitational waves together will tell us exactly what causes a short GRB," said Lindy Blackburn, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and a member of the LIGO Scientific Collaboration. "There is an incredible synergy between the two observations, with gamma rays revealing details about the source's energetics and local environment and gravitational waves providing a unique probe of the dynamics leading up to the event."

Currently, gravitational wave observatories possess relatively blurry vision. This will improve in time as more facilities begin operation, but for the September event, dubbed GW150914 after the date, LIGO scientists could only trace the source to an arc of sky spanning an area of about 600 square degrees, comparable to the angular area on Earth occupied by the United States.

"That's a pretty big haystack to search when your needle is a short GRB, which can be fast and faint, but that´s what our instrument is designed to do," said Eric Burns, a GBM team member at the University of Alabama in Huntsville. "A GBM detection allows us to whittle down the LIGO area and substantially shrinks the haystack."

Less than half a second after LIGO detected gravitational waves, the GBM picked up a faint pulse of high-energy X-rays lasting only about a second. The burst effectively occurred beneath Fermi and at a high angle to the GBM detectors, a situation that limited their ability to establish a precise position. Fortunately, Earth blocked a large swath of the burst´s likely LIGO location from Fermi at the time, allowing scientists to further narrow down the burst´s position.

The GBM team calculates less than a 0.2-percent chance random fluctuations would have occurred in such close proximity to the merger. Assuming the events are connected, the GBM localization and Fermi's view of Earth combine to reduce the LIGO search area by about two- thirds, to 200 square degrees. With a burst better placed for the GBM´s detectors, or one bright enough to be seen by Fermi´s Large Area Telescope, even greater improvements are possible.

The LIGO event was produced by the merger of two relatively large black holes, each about 30 times the mass of the sun. Binary systems with black holes this big were not expected to be common, and many questions remain about the nature and origin of the system.

Black hole mergers were not expected to emit significant X-ray or gamma-ray signals because orbiting gas is needed to generate light. Theorists expected any gas around binary black holes would have been swept up long before their final plunge. For this reason, some astronomers view the GBM burst as most likely a coincidence and unrelated to GW150914. Others have developed alternative scenarios where merging black holes could create observable gamma-ray emission. It will take further detections to clarify what really happens when black holes collide.

Albert Einstein predicted the existence of gravitational waves in his general theory of relativity a century ago, and scientists have been attempting to detect them for 50 years. Einstein pictured these waves as ripples in the fabric of space-time produced by massive, accelerating bodies, such as black holes orbiting each other. Scientists are interested in observing and characterizing these waves to learn more about the sources producing them and about gravity itself.

>From a NASA press release. See the original note with animations at https://www.nasa.gov/feature/goddard/2016/nasas-fermi-telescope-poised-to-pin-down-gravitational-wave-sources

10. No Gravity Waves from Galaxy Mergers - So Far

New results from NANOGrav -- the North American Nanohertz Observatory for Gravitational Waves -- establish astrophysically significant limits in the search for low-frequency gravitational waves. This result provides insight into how often galaxies merge, and how those merging galaxies evolve over time. To obtain this result, scientists required an exquisitely precise, nine-year pulsar-monitoring campaign conducted by two of the most sensitive radio telescopes on Earth, the Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.

The recent LIGO detection of gravitational waves from merging black holes with tens of solar masses has confirmed that distortions in the fabric of space-time can be observed and measured. Researchers from the NANOGrav have spent the past decade searching for low-frequency gravitational waves emitted by black hole binaries with masses many millions of times larger than those seen by LIGO.

Analysis of NANOGrav's nine-year dataset provides very constraining limits on the prevalence of such supermassive black hole binaries throughout the universe. Given scientists' current understanding of how often galaxies merge, these limits point to fewer detectable supermassive black hole binaries than were previously expected. This result has significant impacts on our understanding of how galaxies and their central black holes co-evolve.

Low-frequency gravitational waves are very difficult to detect, with wavelengths spanning light-years, and originating from black hole binaries in galaxies spread across the sky. The combination of all these giant binary black holes leads to a constant "hum" of gravitational waves that models predict should be detectable at Earth. Astrophysicists call this effect the "stochastic gravitational wave background", and detecting it requires special analysis techniques.

Pulsars are the cores of massive stars left behind after stars go Supernova. They emit pulses of radio waves as they spin. The fastest pulsars rotate hundreds of times each second and emit a pulse every few milliseconds. These "millisecond pulsars" (MSPs) are considered nature's most precise clocks and are ideal for detecting the small signal from gravitational waves. The gravitational wave background imprints a unique signature onto the radio waves seen from a collection of MSPs.

Astrophysicists use computer models to predict how often galaxies merge and form supermassive black hole binaries. Those models use several simplifying assumptions about how black hole binaries evolve when they predict the strength of the stochastic gravitational wave background. By using information about galaxy mergers and constraints on the background, the scientists are able to improve their assumptions about black hole binary evolution.

After nine years of observing a collection of MSPs no stochastic background has been detected. This is beginning to rule out many predictions based on current models of galaxy evolution.

There are two possible interpretations of the non-detection. Some supermassive black hole binaries may not be in circular orbits or are significantly interacting with gas or stars. This would drive them to merge faster than simple models have assumed in the past. An alternate explanation is that many of these binaries spiral together too slowly to ever emit detectable gravitational waves.

NANOGrav is currently monitoring 54 pulsars, using the U.S. National Science Foundation's Green Bank Telescope in West Virginia and Arecibo Radio Observatory in Puerto Rico, the two most sensitive radio telescopes at these frequencies. Their array of pulsars is continually growing as new MSPs are discovered. In addition, the group collaborates with radio astronomers in Europe and Australia as part of the International Pulsar Timing Array, giving them access to many more pulsar observations. Ellis estimates that this increase in sensitivity could lead to a detection in as little as five years.

In addition, this measurement helps constrain the properties of cosmic strings, very dense and thin cosmological objects, which many theorists believe evolved when the universe was just a fraction of a second old. These strings can form loops, which then decay through gravitational wave emission. The most conservative NANOGrav limit on cosmic string tension is the most stringent limit to date, and will continue to improve as NANOGrav continues operating.

-- From a NANOGrav and U.S. National Radio Astronomy Observatory press release forwarded by Karen Pollard. See the originals with text, image, and animation at http://nanograv.org/press/ and https://public.nrao.edu/news/pressreleases/2016-nanograv-sbr

11. Two Nearby Supernovae in 'Recent' Times

It´s a classic doomsday scenario. A nearby star explodes in a brilliant supernova, pumping out more energy in a split second than the Sun will emit in a billion years. The blast showers Earth with radioactive elements that destroy the ozone layer and genetically mutate life. But even though astronomers think a nearby star (that is, within 100 light-years of Earth) explodes every million years or so - although not every one has such devastating results - definitive proof has been hard to pin down.

For more than half a century, scientists have recognized two tantalizing clues that nearby supernovae might have showered the Earth roughly 2 million years ago. The first lies in sea-floor sediments where an isotope of iron, iron-60, is found. Iron-60 has a half-life is only 2.6 million years so must be the result of something recent on the geological timescale. The other hint is the Local Bubble - a vast peanut-shaped and plasma-filled cavity surrounding the Sun. Nearby supernova probably carved out this bubble as well.

Now Dieter Breitschwerdt (Berlin Institute of Technology) and colleagues have put these pieces together to pinpoint the likely locations of ancient supernovae. The results published April 7th in Nature, show that two supernovae, both roughly 300 light-years away, exploded 1.5 million and 2.3 million years ago.

To find stars that likely died millions of years ago, Breitschwerdt´s team started with their surviving family. All stars are born within clusters of hundreds to thousands of stars across a wide range of masses. A cluster´s highest-mass stars explode first, while lower-mass siblings live longer. So when astronomers spot a cluster made of only low-mass stars, they assume the missing high-mass stars have already gone supernovae.

After digging through archived Hipparcos data, Breitschwerdt and his colleagues found just the family they were looking for: a group of some 70 low-mass stars. The team then estimated the masses of heavyweight stars presumed missing from that cluster - which told them how long those stars would have lived - in order to pin down exactly when those stars would have exploded.

Breitschwerdt and his colleagues calculated that 16 supernovae in the cluster exploded during the past 13 million years. They ran computer simulations to show how those supernovae might have carved a bubble in space - and the results perfectly matched maps of the Local Bubble. This result alone was exciting enough. But Breitschwerdt wanted to see if he could also make the leap between this result and the iron-60 deposited on the ocean floor.

The presence of iron-60 - an isotope that´s almost exclusively created in supernova explosions - in Earth´s deep-sea crusts allowed the team to nail down a specific time-period to look for the supernovae explosions. The astronomers counted iron-60 layers, and found that one layer was deposited roughly 2.2 million years ago.

It was immediately evident that two of their supernovae had occurred around that time. But in order to verify that these supernovae were the true culprits, the team first had to calculate how the iron-60 fused in the stellar core gets mixed into the blast wave that eventually hits Earth. Breitschwerdt´s calculations show that two supernovae - one that occurred 2.3 million years ago and one that occurred 1.5 million years ago - contributed roughly half of all the iron-60. The rest comes from all the other supernovae combined.

Fortuitously, another paper released in Nature by Anton Wallner (Australian National University) reports iron-60 in crust samples from four different locations in the Pacific, Atlantic, and Indian Oceans. Evidence from multiple locations is exactly what scientists expect to see, given that supernovae would have rained the isotope down across the entire globe.

Would early humans have been affected by the celestial explosions? Adrian Melott (University of Kansas) is working on that answer now. The Nature papers refer to supernovae within several hundred light-years, but supernovae have to be much closer to do any real damage, he says. "What we call the kill zone - where you get a really big mass extinction - is like 8 or 10 parsecs [26 to 33 light-years]". So the effects of supernovae at several hundred light-years from Earth won´t be large.

12. Evidence from 1917 of Exoplanetary System

A spectrum obtained in 1917 of a nearby lone white dwarf star indicates that it has rocky planets orbiting it. Van Maanen's star, named after its discoverer, was identified as a probable nearby star in 1917 from its large proper motion, its movement against background stars. Later measures put it distance at 13.9 light-years.

The spectrum obtained with the Mt Wilson 100-inch (2.5-metre) telescope -- then the world's biggest -- showed that it was a white dwarf star, a little hotter than the sun. A detail in the spectrum that was overlooked until now was the presence of heavier elements, such as calcium, magnesium, and iron, which should have long since disappeared into the star's interior due to their weight.

White dwarfs with heavy elements in their spectra represent a type of planetary system featuring vast rings of rocky planetary remnants that deposit debris into the stellar atmosphere. These recently discovered systems are called "polluted white dwarfs." They were a surprise to astronomers, because white dwarfs are stars like our own Sun at the end of their lifetimes, so it was not at all expected that they would have leftover planetary material around them at that stage.

The mechanism that creates the rings of planetary debris, and the deposition onto the stellar atmosphere, requires the gravitational influence of full-fledged planets. Planets themselves have not yet been detected orbiting van Maanen's star, nor around similar systems, but Jay Farihi, who noticed the absorption lines due to the heavy elements, is confident it is only a matter of time.

-- For the full Carnegie press release, with the spectrum, see https://carnegiescience.edu/node/2019 Thanks to John Arnold of Canterbury University's EPS Library for pointing out this item.

13. Correction: Radio Interferometry's 70th Anniversary

Last month's Newsletter Item 11 was erroneously headed "Radio Astronomy's 70th Anniversary". The article itself made it clear that it was radio _interferometry_ that was 70 years old last January, not radio astronomy.

Radio astronomy had its beginnings when Karl Jansky of Bell Telephone Laboratories discovered radio noise from the Milky Way in 1933. His discovery was followed up by Grote Reber in 1937 and by others after World War II.

14. 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'.

15. 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., R O'Keeffe, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697

16. 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 2016. 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. R O'Keeffe, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697.

17. Quotes

"The greatest possible irony would be if in our endless quest to fill our lives with comfort and happiness we created a world that had neither." -- Bill Bryson

"Too much of a good thing is wonderful." -- Mae West.

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