RASNZ Electronic Newsletter November 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 191

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.


1. Clive Rowe ONZM (1934-2016)
2. Foxton Beach Astrophotography Weekend 25-27 November
3. Aurora & Solar Section - Director Sought
4. The Solar System in December
5. Star Parties in Early 2017
6. 2017 Conference - Call for Papers
7. Variable Star Notes
8. GLEAM Radio Sky Survey Published
9. NZ's Oldest Telescope
10. Planet Nine Tilting the Solar System?
11. How to Join the RASNZ
12. Gifford-Eiby Lecture Fund

1. Clive Rowe ONZM (1934-2016)

Last Tuesday Ashley Marles advised the nzastronomers Yahoo group that Clive Rowe had died. Ashley included with the note several photos of Clive from the Canterbury Astronomical Society's archive. Presumably an illustrated obituary for Clive will appear in Southern Stars. Below are memories from the Editor, Bob Evans and Rod Austin in roughly chronological order.

Alan Gilmore recalls:

I met Clive in March 1960 at the first RASNZ monthly meeting I attended. (The RASNZ used to have monthly meetings in Wellington before the Wellington Astronomical Society was formed.) Clive was boarding with an aunt and uncle in Lower Hutt while working at (I think) the DSIR's Physics & Engineering Lab. He later moved to Philips EDAC (Electronic Development and Application?) in Wellington. He was already experimenting with photomultiplier tubes. I recall us watching a current fluctuation as Sirius crossed the field of a photomultiplier in Clive's telescope. Clive introduced me to Sky & Telescope magazine.

Clive had many adventures applying electronics for EDAC. One he ruefully reported was having to dig holes in the shingle under the newly-opened Haast bridge to attach strain gauges to piers; part of a Ministry of Works research project.

Clive, along with Tom Richards, Steward Mawson, one or two others and me, were selected by the RASNZ to help Charles Michie operate a camera at the Matauri Bay total solar eclipse in May 1965. We were kindly billeted by local farm friends of Mr Michie's. As well as helping take photos with Mr Michie's big camera, Clive got pictures with his 35mm camera. I have a hilarious memory of a sleeping bag rolling around on the ground with Clive's legs sticking out the open end and swearing coming from the closed end as he tried to load the film into a developing tank. Gordon Hudson showed a NZ National Film Unit item on the eclipse at a RASNZ Conference some years back. The RASNZ team appeared there. Val Federoff, another RASNZ member, was on the Film Unit's staff.

It was at a gathering at Clive's place in Lower Hutt after the eclipse that he showed us the first integrated circuit we had seen. The little plastic lozenge contained an amazing eight transistors! Clive immediately saw how such devices could be employed with photomultipliers for photometry. He developed a current-to-frequency converter that was a world first, I understand. Certainly he was invited to the US to show it to people at Kitt Peak and other observatories. He got to drive Helmut Abt's Mustang in Tucson, if I recall correctly.

Clive was involved with many astronomy projects around Wellington in his time there. He gave the old Wellington College Observatory a photometer. Alan Baldwin was a pupil there at the time and recalls: "My most vivid memory of Clive's activity at Gifford Observatory (1961?) was this grey box arriving packed with large glowing valves - very impressive but in reality we had little idea what was being achieved." Clive also helped Taita College get its observatory going.

It was Clive's photoelectric gear that got photometry going at West Melton and at Auckland Observatory. Bob Evans and Rod Austin recount this below.

Clive moved to Christchurch in the late 1960s to work at Canterbury University as an electronics technician. One of his jobs was helping an Electrical and Electronic Engineering academic make ultra-sound 'radar' devices to assist blind people. He later moved to Philips as a salesman of electronic equipment.

In Christchurch Clive was a keen member of the Canterbury Astronomical Society much involved with the development of the observatory complex at West Melton. Clive was also involved with South Island Stardates. The first was held inland somewhere near Castle Hill, from my memories of others' reports. Subsequent SI Stardates were at Staveley where Clive sometimes arrived in his microlite plane, landing in a nearby paddock. He had some hairy adventures in Canterbury nor'westers in that plane.

Later Clive returned to Canterbury University where, among much else, he was involved with setting up the ring laser in the Cashmere Cavern. Sadly it was a victim of the Christchurch earthquakes.

After retirement Clive moved to Waddington, on the West Coast Road. There he set up an ex-Canterbury University aluminizing plant. He re-aluminized some 90 mirrors before moving to Nelson. Unable to find a local home the aluminizing plant was moved to Australia. Just three weeks ago Clive told Gordon Hudson that he and Peter Knowles had built a prototype aluminizing plant to take 12-inch mirrors. They were looking at scaling it up to 24 inches.

An all-round nice and helpful bloke who will be sadly missed. ----

Bob Evans recalls: I first met Clive in Lower Hutt when I and Frank Andrews visited Wellington to discuss plans with the RASNZ for the Joyce Observatory at West Melton (around about 1963 I think). Clive and I, just as others have found, immediately 'hit it off'. As has already been said, Clive's later involvement with the observatory at West Melton was seminal for NZ Astronomy.

In January 1969 Stefan Mochnacki and I were driving to Auckland for a visit, and when Clive learned of this he asked us to take his photometer with us for the Auckland crowd to try out on their telescope at the Auckland Observatory. They had it for a week and Auckland photometry has never looked back. This is just one example of Clive's legacy. ----

Rod Austin adds: I heard the news from Bill Allen last night we have lost one of the most important members of our community. I first met Clive in 1969 when I got involved with the CAS photometer project. Clive was my mentor right through my time at Mt John too. A true friend and enthusiast who had the knack of being able to explain physical and astronomical phenomena by the simplest ways to give a full understanding of the processes involved. There seemed to be nothing he couldn't do. A real gentleman and awesome friend. We are going to truly miss him. ----

Raewyn Newnham advises that two services will be held, the first one will be Clive's funeral and will be held in Nelson: Monday 21st November at 1:30 pm, St Barnabas Anglican Church, 523 Main Road, Stoke, Nelson, followed by a tea/coffee in the reception area.

The second one is a Memorial Service and will be in Christchurch: Saturday 26th November at 1:30 pm, St Ninians Presbyterian Church, 5 Puriri Street, Riccarton, Christchurch, followed by a tea/coffee in the rear lounge.

Messages to Marilyn Rowe, 27 Somerset Tce, Stoke, Nelson; email: This email address is being protected from spambots. You need JavaScript enabled to view it.; Phone 03 553 0442.

2. Foxton Beach Astrophotography Weekend 25-27 November

The Horowhenua Astronomical Society is hosting the fourth New Zealand Astrophotography Weekend at the Foxton Beach Bible Camp. This is an annual event dedicated to astrophotography in a wonderful dark-sky location. It is open to everyone interested in astrophotography - from beginners to advanced. Come along and share your knowledge, tips and experiences. All sorts of astrophotography can be undertaken - solar- system/nightscapes/deep-sky.

The weekend will consist of: practical astrophotography, image processing, presentations, bring-and-buy. Everyone is encouraged to bring along their own telescopes, binoculars, mounts, cameras, etc, however basic they might be. There are plenty of safe areas for people to set up their equipment and leave it in situ for the whole weekend.

Due to high demand numbers will be restricted so please book early to avoid disappointment.

For registration, accommodation options, etc, see http://www.horoastronomy.org.nz/upcoming-events/astrophotography-weekend

-- From the above website.

3. Aurora & Solar Section - Director Sought

I have decided to relinquish directorship of the Section at the end of this year. I became involved in assisting in administering the Section in 1985 and gradually got more involved over the next few years. After these three decades I'd like to now devote my time to other projects; including hopefully more observational astronomy.

I don't know whether there is anyone out there that is interested in taking over the running of the Section. I hope that there might be. It would no doubt be in a different form. It could even be split into a separate Aurora Section and a Solar Section. The only requirement for it to be a Section of the RASNZ is that the Director needs to be an RASNZ member and that the RASNZ Council approves it being a Section.

My reasons for running the Section has been twofold: to compile a record of the occurrences and descriptions of Aurorae Australis and the Sun, and to encourage their observation. These observations have been detailed in Circulars, starting with auroral observations early in 1979, then by Dennis Goodman who was the Section Director at that time. I am in the process of scanning all these records and uploading them to the RASNZ Website.

I intend publishing two more Newsletters that will summarise observation up to the end of this year, and one more Circular detailing 2016 observations.

I am happy to discuss with anyone interested in continuing this Section in some form or other or they May apply directly to the RASNZ Council via its Secretary.

-- Bob Evans.

4. The Solar System in December

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

Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in december

                          December  1  NZDT             December 31 NZDT
                  morning  evening              morning  evening
       SUN: rise: 5.39am,  set: 8.40pm     rise: 5.47am,  set: 8.59pm
Civil:    starts: 5.10am, ends: 9.11pm   starts: 5.17am, ends: 9.31pm
Nautical: starts: 4.28am, ends: 9.52pm   starts: 4.34am, ends:10.14pm
Astro:    starts: 3.40am  ends:10.41pm   starts: 3.43am, ends:11.05pm

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

          First quarter: December  7 at 10.03 pm (09:03 UT)
  Full moon:     December 14 at  1.06 pm (00:06 UT)
  Last quarter   December 21 at  2.56 pm (01:56 UT)
  New moon:      December 29 at  7.53 pm (06:53 UT)

The SOUTHERN SUMMER SOLSTICE is on 2016 December 21 at 11.45 pm NZDT (10:45 UT)

The planets in December

Venus remains the most obvious planet in the evening sky. Mars, much fainter, is higher in the sky. Mercury May be briefly visible low in the evening sky about an hour after sunset. It will disappear after about mid month. Jupiter is the only planet visible in the morning sky. Saturn is not likely to be seen during December.

MERCURY starts December as an evening object with a magnitude -0.5. On the 1st it will set nearly 100 minutes after the Sun. An hour after sunset, shortly before the end of nautical twilight, the planet will be 5° up in a direction 30° to the south of west. Venus will be some 25° away to its upper right.

Throughout the first half of December Mercury will continue to set up to 100 minutes after the Sun. It reaches its greatest elongation, 21° east of the Sun, on the 11th. After mid December the distance of Mercury from the Sun starts decreasing, so it sets earlier. As a result it will be lost in the evening twilight within a few days. The planet is at inferior conjunction between the Earth and Sun on December 29, when it will be 101 million km, 0.675AU, from the Earth and 0.311AU from the Sun.

VENUS will remain a brilliant light in the evening sky throughout December reaching magnitude -4.4. It sets shortly before midnight throughout the month. The planet starts December in Sagittarius but, moving to the east, crosses into Capricornus on the 7th. By the 31st Venus will have moved crossed to the eastern edge of the constellation.

The crescent moon will be 6.5° from Venus on the evening of December 3.

MARS starts December in Capricornus at magnitude 0.6. With a distinctly orange colour it will be some 25° to the upper right of Venus. On December 3 Mars passes close to the star iota cap (mag 4.3). They will be closest about 9.30 pm, some 50 minutes after sunset in Wellington, when only 40 arc-seconds apart. about 1% of the moon's diameter. At this distance they will be almost impossible to separate by eye, but fairly easy to do so using binoculars. By midnight Mars will have moved to be just over 4 arc-minutes from the star

Two days later the crescent moon will be 3.5° from Mars.

In mid December Mars moves into Aquarius. It movement across the constellation will be slower than Venus's in Capricornus, as a result the two will be only 12° apart on the 31st. On that evening Mars will have almost caught up Neptune, their separation being some 40 arc- minutes.

JUPITER remains the only one of the naked eye in the December morning sky. On the 1st it rises at 3.15 am, advancing to about 1.30 am by the 31st. The planet is in Virgo, its distance from Spica decreasing from 8 to 4.5° during the month.

On the morning of the 23rd, the moon a day past third quarter, will be just over 3° from Jupiter.

SATURN is at conjunction with the Sun on December 10 so will not be observable during December. At conjunction Saturn will be 1650 million km, 11 au, from the Earth, 10 AU beyond the Sun. By the end of the month it will rise in the morning sky about 75 minutes before the Sun.

Outer Planets

URANUS, at magnitude 5.7, remains in Pisces and is observable all evening. It sets close to 3.30 am on the 1st and two hours earlier on the 31st. The planet is stationary on the 30th. As a result its position changes very little during December, by a distance equivalent to only two-thirds of the diameter of the full moon.

NEPTUNE is in Aquarius at magnitude 7.9 throughout December. It sets about 2 am on the 1st, and midnight at the end of December. The moon is closest to Neptune on the 6th but still 6° at midnight. A few hours later the moon will occult the planet as seen from the northern Atlantic region including northeast Canada and much of Greenland. Mars will close in on Neptune during December.

PLUTO at magnitude 14.5 is very low in the early evening sky. It is in Sagittarius setting only 20 minutes after the Sun by the end of December.

Minor Planets

(1) CERES continues in Cetus during December with its magnitude fading from 8.2 to 8.6. It is stationary mid month resulting in most of its apparent motion being to the north so ending the month some 7° from Uranus.

(18) MELPOMENE is also in Cetus between 9 and 11 degrees from Ceres. The asteroid, diameter 148 km, fades from magnitude 8.9 to 9.6 during December. Melpomene is on the opposite side of Ceres to Uranus.

Both Ceres and Melpomene are visible all evening not setting until well after midnight.

(4) VESTA is in Cancer throughout December rising about 12.15 am on the 1st and two hours earlier on the 31st. Its magnitude brightens from 7.4 to 6.7 during the month. Vesta starts December 2° from the Beehive cluster, M44. Its westerly retrograde motion sees the asteroid move away from the cluster so that by the 31st they will be 5 degrees apart.

-- Brian Loader

5. Star Parties in Early 2017

Central Star Party: Thursday 19th - Monday 23rd January. The Central Star Party has been established to hold annual star parties in the central North Island for the benefit of the astronomical community of the North Island of New Zealand. The goal of the organisers is to provide a fun social astronomical gathering laced with talks and activities and star gazing. The second Central Star Party is Thursday 19th to Mon 23rd January 2017 and be held at the Tuki Tuki Camp site in the Hawkes Bay. This is the site of many previous star parties. There is a brand new hall, with two additional meeting rooms for alternate meetings, a new kitchen and three new dormitories. Accommodation is tenting, staying in the dormitories or using one of the six powered caravan sites. For more details go to - http://www.censtar.party/

Stardate NI (North Island): Friday 27th - Sunday 29th January. Richard Hall writes, `Stardate 2017 is to be held at Stonehenge Aotearoa on January 27th to 29th 2017. However, participants May arrive earlier or stay later than these dates. In addition to a 3-day program of astronomical lectures, workshops and observing, we have movies, a geology field trip, live music and of course barbecues. This is an attractive site with good swimming holes in the Ruamahanga River just down the road. The wine growing areas of Martinborough, Gladstone and Masterton are within 30 minutes. There is a thriving tourist industry with many activities and venues available within the same distance´. For further information phone (06) 377 1600 or visit www.astronomynz.org

Stardate SI (South Island): Friday 17th - Monday 20th February. Stardate SI will be held at a "Christian" hostel and camp at Staveley between Friday February Friday 17th to Monday 20th February 2017. Organiser Euan Mason writes, `There's nothing particularly religious about Stardate, although Phil Barker reports a religious experience when he views the cosmos through his twin brother Kevin's 5" Zeiss refractor. Come and join us for this magnificent celebration of astronomy, science, and the cosmos at large´. For more details see - http://www.treesandstars.com/stardate/

-- From 'Keeping in Touch' #19. 23 October 2016

6. 2017 Conference - Call for Papers

It is a pleasure to announce that 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. Our guest speaker will be Professor Joss Bland-Hawthorn from the University of Sydney, and the Fellows´ Lecture for 2017 will be delivered by Jennie McCormick. Titles and abstracts for these talks will be released when they are available.

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. Please note that you must be registered for the conference to give an oral presentation and for your convenience a link has been provided if you wish to do this when you register.

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 will be 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.

For further information on the RASNZ conference, registration details and associated events please visit the conference website at www.rasnz.org.nz/Conference

-- Warwick Kissling, RASNZ Standing Conference Committee.

7. Variable Star News - TT Cen, Nova Sgr

TT Cen

The November 2016 Newsletter of AAVSO features the variable TT Cen. This star is a Mira type variable which is listed in the GCVS as having a period of 462 days with a magnitude range of 11.5 to fainter than 16.5. Its discovery was reported by Shapley and Swope in 1940 and it was noted as having a "dual maximum" around mag 13.

The observations in the AAVSO database date from the 1970s; despite the short history there have been significant changes in the light curve. The brightness at maximum up until about 2005 was much brighter than the GCVS value (mag 8.5 as opposed to 11.5). However, at this point the maximum brightness started to decrease quite rapidly to around the original GCVS value of mag 11.5 by 2012. Since 2012 the maximum has started to brighten somewhat.

An analysis of the period over the last 18,000 days shows a regular and relatively smooth variation from approximately 467 days decreasing to 447 days by 1992 and back up to 460 days by 2009. This is not uncommon in very long period (>400 days) Mira which can show evidence of "meandering" periods.

TT Cen has also undergone some remarkable spectral changes as recorded by Stephenson (1973), who summarized evidence that it May have recently changed from showing dominantly S-type to dominantly C-type characteristics. If this is the case, then it is probably the result of dredge-up following a recent helium shell flash.

For further information on this star refer to the original AAVSO article, and an article by S Walker et al in the RASNZ Variable Stars South Newsletter, April 2016 on the VSS web-site which documents BVRI observations through a cycle.

-- Alan Baldwin ----------

Nova in Sagittarius

A nova in Sagittarius reached magnitude 5.5 on November 8 and is now in decline. It was magnitude 7.5 on November 18. The nova was discovered at V magnitude 13.7 on October 25 by the ASASSN group who designated it ASASSN-16ma. The IAU Central Bureau has given it the temporary designation = PNV J18205200-2822100 based on the objects coordinates of (2000) R.A. 18 20 52.25 Dec. -28 22 12.1. With Sagittarius sinking in the western twilight the nova won't be accessible much longer.

-- From notes supplied by Alan Baldwin

8. GLEAM Radio Sky Survey Published

Victoria University of Wellington astrophysicists are part of an international team that has released one of the widest-ever radio wave surveys of the Universe and the first to reveal it in such technicolour detail.

Victoria Associate Professor of Physics Melanie Johnston-Hollitt and postdoctoral fellows Dr Cathie Zheng and Dr Luke Hindson were the New Zealand arm of a 19-strong multi-country team that designed and executed the survey and processed the data.

Published in the Monthly Notices of the Royal Astronomical Society on October 27, the GaLactic and Extragalactic All-sky MWA, or GLEAM, survey has produced a catalogue of 300,000 galaxies observed at frequencies from 70 to 230 MHz by the Murchison Widefield Array (MWA), a $50 million radio telescope located at a remote site in the West Australian outback.

Lead author Dr Natasha Hurley-Walker, from Curtin University and the International Centre for Radio Astronomy Research (ICRAR), said this is the first radio survey to image the sky in such amazing technicolour. "The human eye sees by comparing brightness in three different primary colours - red, green and blue," Dr Hurley-Walker said. "GLEAM does rather better than that, viewing the sky in 20 primary colours. "That´s much better than we humans can manage, and it even beats the very best in the animal kingdom, the mantis shrimp, which can see 12 different primary colours," she said.

GLEAM is a large-scale, high-resolution survey of the radio sky observed at frequencies from 70 to 230 MHz, observing radio waves that have been travelling through space - some for billions of years. "Our team are using this survey to find out what happens when clusters of galaxies collide," Dr Hurley-Walker said.

"We´re also able to see the remnants of explosions from the most ancient stars in our galaxy, and find the first and last gasps of supermassive black holes."

MWA Director Associate Professor Randall Wayth, from Curtin University and ICRAR, said GLEAM is one of the biggest radio surveys of the sky ever assembled. "The area surveyed is enormous," he said. "Large sky surveys like this are extremely valuable to scientists and they´re used across many areas of astrophysics, often in ways the original researchers could never have imagined," Associate Professor Wayth said.

Completing the GLEAM survey with the MWA is a big step on the path to SKA-low, the low frequency part of the international Square Kilometre Array (SKA) radio telescope to be built in Australia in the coming years.

"It´s a significant achievement for the MWA telescope and the team of researchers that have worked on the GLEAM survey," Associate Professor Wayth said. "The survey gives us a glimpse of the Universe that SKA-low will be probing once it´s built. By mapping the sky in this way we can help fine-tune the design for the SKA and prepare for even deeper observations into the distant Universe."

View more at http://www.icrar.org/gleam/

-- From the Royal Society of New Zealand Alert newsletter 932, 27 October, and from the above website.

9. NZ's Oldest Telescope

Otago Museum has discovered that it is home to what appears to be the oldest telescope in New Zealand.

Both the Otago Museum and Space Place in Wellington have telescopes within their collections made by James Short (1710-1768), a highly significant 18th century telescope maker, who studied classics, divinity and mathematics at Edinburgh University. Space Place holds a telescope dated to 1758, but Otago Museum´s instrument is 22 years older, having been made in 1736.

The provenance of the telescope was uncovered as a result of research being undertaken by Dr William Tobin, a former Senior Lecturer in the Physics and Astronomy Department at the University of Canterbury.

Otago Museum´s telescope has a 41/93 serial number, meaning it was the 93rd telescope made by Short, and the 41st of that particular size. Its main metal mirror has a diameter of about 60mm. This particular telescope was made in Edinburgh before Short moved to London in 1738 and was previously owned by local astronomer John Campbell Begg, who was instrumental in setting up Dunedin´s Beverly Begg Observatory. It was donated to the Museum by his son, John Wyndham Begg.

Captain James Cook took two of Short´s instruments on the Endeavour to observe the Transit of Venus in 1769.

Otago Museum Director Ian Griffin is thrilled that Dr Tobin has unearthed the history of its James Short telescope, again highlighting the depth and breadth of the Museum´s collection.

"We are delighted to be able to say we are home to the oldest telescope in the country, an announcement that is very timely as we approach the first birthday of the Perpetual Guardian Planetarium," says Griffin.

"To the best of our knowledge, and based on the findings by Dr Tobin, this is the oldest telescope in the country - but of course, we´d love to hear from anyone who thinks they might have an older one." The Dodd-Walls Centre for Photonic and Quantum Technologies has offered to fund the instrument´s conservation, which will allow the Museum to have the telescope on display to its visitors in the near future.

"The Dodd-Walls Centre was established based on New Zealand's outstanding heritage in quantum optics. It is only fitting that we help support the preservation and display of New Zealand's oldest telescope as direct lineage of this optics tradition," says Director of the Dodd- Walls Centre for Photonic and Quantum Technologies, Professor David Hutchinson.

Another strong link between the Begg family and the Otago Museum is the `Interplanetary Cycle Trail´ - a project that will see a scale model of the solar system at various points along the Otago Central Rail Trail. The project is a collaboration between the Otago Central Rail Trail Trust and the Otago Museum, and was inspired by Ian Begg, the grandson of John Campbell Begg.

-- Otago Museum press release.

10. Planet Nine Tilting the Solar System?

"Planet Nine", which May lurk beyond Neptune, May be the reason that the solar system's planets orbit at a six-degree angle with respect to the Sun. The undiscovered planet was predicted by the work of Caltech's Konstantin Batygin and Mike Brown in January 2016 appears to be responsible for the unusual tilt of the Sun, according to a new study.

The tilt of the solar system's orbital plane to the sun's equator has long puzzled astronomers. All current evidence is that planetary systems start with a spinning cloud that slowly collapses, first into a disk and then into objects orbiting a central star. The central star's equator should be in the plane of the planetary system.

Brown and Batygin's discovery of evidence that the Sun is orbited by an as-yet-unseen planet - about 10 times the size of Earth in an orbit about 20 times farther from the Sun on average than Neptune's - changes the physics. Planet Nine, based on their calculations, appears to orbit at about 30 degrees off from the other planets' orbital plane. It influences the orbits of a large population of objects in the Kuiper Belt. This is how Brown and Batygin came to suspect a planet existed there in the first place.

Planet Nine's angular momentum is having an outsized impact on the solar system based on its location and size. A planet's angular momentum equals the mass of an object multiplied by its distance from the Sun, and corresponds with the force that the planet exerts on the overall system's spin. Because the other planets in the solar system all exist along a flat plane, their angular momentum works to keep the whole disk spinning smoothly.

Planet Nine's unusual orbit, however, adds a multi-billion-year wobble to that system. Mathematically, given the hypothesized size and distance of Planet Nine, a six-degree tilt fits perfectly, Brown says.

"Because Planet Nine is so massive and has an orbit tilted compared to the other planets, the solar system has no choice but to slowly twist out of alignment," says Elizabeth Bailey, a graduate student at Caltech and lead author of a study announcing the discovery.

The next question, then, is how did Planet Nine achieve its unusual orbit? Though that remains to be determined, Batygin suggests that the planet May have been ejected from the neighbourhood of the gas giants by Jupiter, or perhaps May have been influenced by the gravitational pull of other stars in the solar system's extreme past.

For now, Brown and Batygin continue to work with colleagues throughout the world to search the night sky for signs of Planet Nine along the path they predicted in January. That search, Brown says, May take three years or more.

For the original text and images see http://www.caltech.edu/news

The paper is "Solar Obliquity Induced by Planet Nine," Elizabeth Bailey, Konstantin Batygin & Michael E. Brown, 2016, Astrophysical Journal. http://apj.aas.org, preprint: https://arxiv.org/abs/1607.03963

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

11. 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'.

12. 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.


"Science is written down in papers, but the juicy stories not." -- Solar-Terrestrial Centre of Excellence (STCE) fourth week October Newsletter, passed on by Bob Evans.

"You never tire of the natural world. Putting your feet up is all very well, but it's very boring, isn't it?" -- David Attenborough, 90, quoted in the Independent.

"I know of no safe depository of the ultimate powers of the society but the people themselves: and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education." -- Thomas Jefferson.

"The best argument against democracy is a five-minute conversation with the average voter." -- Winston Churchill.

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