RASNZ_20_04_2019
Royal Astronomical Society of New Zealand
eNewsletter: No. 220, 20 April 2019 Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website www.rasnz.org.nz in their own newsletters provided an acknowledgement of the source is also included.
Contents
1. Black Hole Imaged
2. Roy Kerr named FRS
3. 2019 RASNZ Conference - New Plymouth
4. The Solar System in May
5. Variable Stars South News
6. New Zealand Starlight Conference, October 2019
7. Astronomy for Equity, Diversity and Inclusion
8. 2020 Conference and RASNZ Centenary
9. NZ Post Stamp Issue: New Zealand Space Pioneers
10. LIGO-VIRGO On-Line
11. Exoplanet Directly Observed
12. Magnetic star mapped
13. NASA to Test Asteroid Diversion
14. Pitcairn Islands Newest Astro-Tourism Destination
15. How to Join the RASNZ
16. Kingdon-Tomlinson Fund
17. May Newsletter Will be Late
18. Quote
1. Black Hole Imaged
On April 10 an international collaboration announced that they had imaged a black hole or, more accurately, the shadow of a black hole.
The breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the centre of Messier 87, a massive galaxy 55 million light-years away in the Virgo galaxy cluster. The black hole has a mass 6.5 billion times that of the Sun.
The black hole was seen by combining the output of many widely-spaced radio telescopes in a technique called very-long-baseline interferometry (VLBI). The effect is to form one huge, Earth-size telescope observing at a wavelength of 1.3 mm. VLBI allowed the Event Horizon Telescope (EHT), as the consortium is called, to achieve an angular resolution of 20 micro-arcseconds, about 37mm at the Moon's distance.
The EHT offers scientists a new way to study the most extreme objects in the Universe predicted by Einstein’s general relativity. This is being done in the centenary year of the historic experiment that first confirmed the theory: the measurements of the bending of starlight by the Sun from photos taken during a total solar eclipse.
Black holes are cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping space-time and superheating any surrounding material.
"If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow — something predicted by Einstein’s general relativity that we’ve never seen before," explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. "This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and has allowed us to measure the enormous mass of M87’s black hole."
Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region — the black hole’s shadow — that persisted over multiple independent EHT observations. The shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across.
Creating the EHT was a formidable challenge which required upgrading and connecting a worldwide network of eight pre-existing telescopes deployed at a variety of challenging high-altitude sites. These locations included volcanoes in Hawai`i and Mexico, mountains in Arizona and the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.
The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope.
The East Asian Observatory (EAO) partner on the EHT project represents the participation of many regions in Asia, including China, Japan, Korea, Taiwan, Vietnam, Thailand, Malaysia, India and Indonesia.
Although the telescopes are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. The data was flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration
Adapted from European Southern Observatory release eso1907.
See also https://eventhorizontelescope.org/
Sergei Gulyaev of AUT gave a radio astronomer's perspective on the imaging in a National Radio Morning Report interview at
https://www.radionz.co.nz/national/programmes/morningreport/audio/2018690507/black-hole-image-a-mt-everest-for-nz-science
David Wiltshire of Canterbury University talked about the imaging from a relativity and cosmological viewpoint at https://www.radionz.co.nz/national/programmes/lately/audio/2018690646/roy-kerr-s-black-hole-theory-proven-right
2. Roy Kerr named FRS
University of Canterbury Distinguished Professor Roy Kerr FRSNZ CRSNZ has been named a Fellow of The Royal Society, London. Last week his revolutionary 56-year-old solution of Einstein's equations that describe rotating black holes was proven correct with the first black hole image.
Minimal details at https://royalsociety.org/news/2019/04/royal-society-announces-2019-fellows/
3. 2019 RASNZ Conference - New Plymouth
The annual RASNZ conference will be held in New Plymouth from Friday 17th until Sunday 19th May 2019.
You will find an announcement on RASNZ home page www.rasnz.org.nz - click on the "Read more" button to go to the conference information page. There you will find links to the on-line conference registration form, the online paper submission form, the conference brochure and a downloadable registration form (for those who want to fill out a form manually). Immediately following the conference in New Plymouth the 13th Trans-Tasman Symposium on Occultations will run from Monday to mid-day Tuesday.
For those who wish to take advantage of the special conference rate for accommodation at the venue (the Devon Hotel) the promo code is RASNZ2019. The conference brochure, available for download on the RASNZ's conference webpage has been updated with this information.
The RASNZ Conference webpage is updated with abstracts of papers as they are accepted so keep an eye on that page to see what will be on offer.
-- Glen Rowe, Chair, Standing Conference Committee.
4. The Solar System in May
Dates and times shown are NZST (UT + 12 hours). Rise and Set times are for Wellington. They will vary by a few minutes elsewhere in NZ. Data is adapted from that shown by GUIDE 9.
THE SUN and PLANETS in MAY, Rise & Set, Mag. & Cons.
May 1 NZST May 31 NZST
Mag Cons Rise Set Mag Cons Rise Set
SUN -26.7 Ari 7.04am 5.30pm -26.7 Tau 7.33am 5.03pm
Merc 0.8 Psc 5.20am 4.49pm -0.3 Tau 8.34am 5.37pm
Venus -3.9 Psc 4.43am 4.26pm -3.8 Ari 5.50am 4.01pm
Mars 1.5 Tau 10.29am 7.36pm .1.6 Gem 9.57am 7.02pm
Jup -2.2 Oph 7.45pm 10.47am -2.4 Oph 5.37pm 8.35am
Saturn 0.6 Sgr 9.46pm 12.37pm 0.5 Sgr 7.44pm 10.37am
Uranu 5.9 Ari 6.25am 5.07pm 5.9 Ari 4.35am 3.13pm
Nep 8.0 Aqr 2.36am 3.24pm 7.9 Aqr 12.41am 1.28pm
Pluto 14.5 Sgr 9.56am 12.50pm 14.5 Sgr 7.57pm 10.51am
May 1 NZST May 31 NZST
Twilights morning evening morning evening
Civil: start 6.39am, end 5.57pm start 7.05am, end 5.32pm
Nautical: start 6.06am, end 6.30pm start 6.31am, end 6.06pm
Astro: start 5.34am, end 7.02pm start 5.57am, end 6.39pm
MAY PHASES OF THE MOON, times NZST (& UT)
New moon: May 5 at 10.45am (May 4, 22:45 UT)
First quarter: May 12 at 1.12pm (01:12 UT)
Full Moon: May 19 at 9.11am (May 18, 21:11 UT)
Last quarter May 27 at 4.34am (May, 26 16:34 UT)
PLANETS in May
MERCURY will be visible about an hour before sunrise for the first week of May, a few degrees to the lower right of Venus. The moon, as a very thin crescent will be some 6° above Mercury on the morning of May 3.
Mercury is at superior conjunction on the 21st, so too close to the Sun for observation for the last three weeks of May.
VENUS drops further behind Mercury during May and remains a morning object. It will be readily visible fairly low in the morning twilight. The crescent moon will be to the right of and a little lower then Venus on the morning of May 3.
MARS is the one planet visible in the early evening. It sets about 2 hours after the Sun all month, a low object to the northwest as the sky darkens. On the 8th the crescent moon will be 3.5° above Mars
JUPITER will be easily visible to the east in the second half of the evening during May. It is also visible to the north and then west in the morning. The near full moon is just under 2° from Jupiter on the morning of May 21.
SATURN rises early evening by the end of May, so will readily be visible to the east an hour or two later. This month's occultation by the moon is visible from the south Indian Ocean.
URANUS begins to move up into the morning sky during May. It is one degree to the left of Venus on the morning of May 19.
NEPTUNE is also a morning object. It will be about 3° to the lower left of the moon on the morning of June 28, with the moon just past last quarter
PLUTO is about 3° from Saturn all month.
BRIGHTEST ASTEROIDS in MAY, mag. const. time of transit
MAY 1 NZDT MAY 31 NZST
Mag Cons transit Mag Cons transit
(1) Ceres 7.6 Oph 2.32am 7.0 Sco 12.08am
(2) Pallas 8.3 Boo 11.25pm 8.9 Com 9.15pm
(4) Vesta 8.2 Cet 10.39pm 8.3 Psc 9.30am
CERES rises at 7.24 pm on the 1st and 5 pm on the 31st, being about 12° from Jupiter. The near full moon will be just under 4° to the upper left of Ceres on the evening of May 19 and less than 1° to the left of the asteroid the following morning. Ceres is at opposition on May 28.
PALLAS rises at 6.45 pm on May 1 when it will be 9° from Arcturus. By the end of May it will rise at 4.40 pm, shortly before sunset.
VESTA will be 3.3° to the left of Venus on the morning of May 2, with the moon some 9° above the two. The following morning the three will form a triangle with the moon 3° below Vesta and to the lower right of Venus. Vesta will rise at 3.45 am on the 31st
-- Brian Loader
5. Variable Stars South News
AAVSO Alert U Scorpi
Frequent monitoring is requested of the recurrent nova U Scorpii over the next year or so to discover the upcoming very-fast eruption. The predicted outburst is for the year 2020.0±0.7. The eruption is likely within the next year, but it could well go off tonight. For details of procedure to advise an outburst refer to AAVSO Alert 664. Visual and CCD/DSLR observers are requested to observe as frequently as possible.
The importance of this is supported by the following data: rise to maximum outburst about 6 h; time to fade to < mag 10.5 2.6 days.
For details see https://www.aavso.org/aavso-alert-notice-664
AAVSO On-Line Courses
Upcoming AAVSO CHOICE courses:: How to use VStar (May 6 - 31); NEW! Observing and Counting Sunspots (June 3 - 14); Developing a Visual Observing Program (August 5 - 30). From AAVSO Monthly Communication April 2019.
-- Alan Baldwin
6. New Zealand Starlight Conference, October 2019
We are planning a conference on dark skies, combatting light pollution and star gazing to be held at Lake Tekapo, in the world’s largest International Dark Sky Reserve. See http://starlightconference.org/
The dates will be 6 pm on Sunday 20 October 2019 to 4.30 pm on Wednesday 23 October 2019.
The New Zealand Starlight Conference is supported by the International Dark Sky Association and hosted by the Aoraki Mackenzie International Dark Sky Reserve Board.
More details will be posted on the website above in the coming months. Members of RASNZ and affiliated societies will be most welcome as participants.
We hope to see many RASNZ members at the conference.
-- John Hearnshaw, Chair of AMIDSR Board.
7. Astronomy for Equity, Diversity and Inclusion
Grant applications are open for International Astronomical Union Symposium IAUS358 on Astronomy for Equity, Diversity and Inclusion
The International Astronomical Union (IAU) and the National Astronomical Observatory of Japan (NAOJ) will host the first IAU Symposium on "Astronomy for Equity, Diversity and Inclusion -- a roadmap to action within the framework of IAU centennial anniversary" in Tokyo, Japan, from 12-15 November, 2019. IAU grant applications are now open. Please pre-register, submit your abstract and application by 15 June 2019.
Relevant information is at:
Official Website: https://iau-oao.nao.ac.jp/iaus358/
Early Registration: https://iau-oao.nao.ac.jp/iaus358/registration/
Abstract Submission: https://iau-oao.nao.ac.jp/iaus358/abstract-submission/
Grant Application: https://iau-oao.nao.ac.jp/iaus358/iau-travel-grants/
Contact: iaus358contact@prcml.mtk.nao.ac.jp
Important Note: This will be a symposium strongly focused on discussions among participants and interactions between speakers and participants. To optimize the dialogues during the symposium and accommodate all needs, the organization has a participant limit. We therefore recommend all interested to secure an early registration soon.
-- Lina Canas, Assistant Outreach Coordinator, Office for Astronomy Outreach, International Astronomical Union. Passed along by the Royal Society of NZ.
8. 2020 Conference and RASNZ Centenary
The 2020 Conference will be held 8-10 May at Wellington with the Wharewaka Function Centre the venue (near the Michael Fowler Centre) in downtown Wellington. The Wellington Astronomical Society is hosting this conference.
2020 marks a significant milestone in the life of the Society as it was founded in November 1920 with 75 members.
The SCC invites ideas from members how the Society might commemorate its centenary at next year’s conference. Please send your suggestions to the SCC at conference@rasnz.org.nz.
-- Glen Rowe, Chair, Standing Conference Committee
9. NZ Post Stamp Issue: New Zealand Space Pioneers
Immersed in a clear, unpolluted southern sky, from New Zealand we have more stars and galaxies accessible to the naked eye than in most parts of the Northern Hemisphere. It is not surprising then that for most of New Zealand’s history, the lines between professional and amateur astronomers have been blurred. It is in this spirit that New Zealanders have helped to advance the world’s knowledge about space and space sciences.
For details see
https://stamps.nzpost.co.nz/new-zealand/2019/space-pioneers
Pre order now for 1 May 2019.
10. LIGO-VIRGO On-Line
The LIGO Scientific Collaboration and the Virgo Collaboration report:
Our third observing run ("O3") began as scheduled on 2019 April 1 at 15:00 UTC. At that time the LIGO Hanford, LIGO Livingston, and Virgo
Observatories transitioned from engineering and commissioning to
observing. All three detectors are operating at good sensitivity and
stability. We are analyzing data in low latency and processing candidate
transient events automatically.
As of April 2 20:00 UTC, we have configured our low-latency analysis
pipeline to send public alerts for significant gravitational-wave
transient candidates that are detected in coincidence across two or more
gravitational-wave detectors.
Automated Preliminary GCN Notices will be sent immediately without any
human intervention. Shortly afterward, they will be vetted by an LSC/Virgo rapid response team and either confirmed with an Initial GCN Notice and Circular, or withdrawn with a Retraction.
Retraction notices may be issued more frequently over the next few weeks
as our understanding of the instrumental background improves.
For further information about vetting procedures, analysis methodology,
and the contents of LIGO/Virgo public alerts, refer to the LIGO/Virgo
Public Alerts User Guide.
This marks the beginning of the era of public alerts for the field of
gravitational-wave astronomy.
-- Leo Singer at GSFC/iPTF in GCN CIRCULAR No. 24045
11. Exoplanet Directly Observed
The GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI) has made the first direct observation of an exoplanet using optical interferometry.
This method revealed a complex exoplanetary atmosphere with clouds of iron and silicates swirling in a planet-wide storm. The technique presents unique possibilities for characterising many of the exoplanets known today.
This result was announced today in a letter in the journal Astronomy and Astrophysics by the GRAVITY Collaboration, in which they present observations of the exoplanet HR8799e using optical interferometry. The exoplanet was discovered in 2010 orbiting the young main-sequence star HR8799, which lies around 129 light-years from Earth in the constellation of Pegasus.
Today’s result, which reveals new characteristics of HR8799e, required an instrument with very high resolution and sensitivity. GRAVITY can use ESO’s VLT’s four 8.2-metre unit telescopes to work together to mimic a single larger telescope using a technique known as interferometry. This creates a super-telescope — the VLTI — that collects and precisely disentangles the light from HR8799e’s atmosphere and the light from its parent star.
HR8799e is a ‘super-Jupiter’, a world unlike any found in our Solar System, that is both more massive and much younger than any planet orbiting the Sun. At only 30 million years old, this baby exoplanet is young enough to give scientists a window onto the formation of planets and planetary systems. The exoplanet is thoroughly inhospitable — leftover energy from its formation and a powerful greenhouse effect heat HR8799e to a hostile temperature of roughly 1000 °C.
This is the first time that optical interferometry has been used to reveal details of an exoplanet, and the new technique furnished an exquisitely detailed spectrum of unprecedented quality — ten times more detailed than earlier observations. The team’s measurements were able to reveal the composition of HR8799e’s atmosphere — which contained some surprises.
“Our analysis showed that HR8799e has an atmosphere containing far more carbon monoxide than methane — something not expected from equilibrium chemistry,” explains team leader Sylvestre Lacour researcher CNRS at the Observatoire de Paris - PSL and the Max Planck Institute for Extraterrestrial Physics. “We can best explain this surprising result with high vertical winds within the atmosphere preventing the carbon monoxide from reacting with hydrogen to form methane.”
The team found that the atmosphere also contains clouds of iron and silicate dust. When combined with the excess of carbon monoxide, this suggests that HR8799e’s atmosphere is engaged in an enormous and violent storm.
“Our observations suggest a ball of gas illuminated from the interior, with rays of warm light swirling through stormy patches of dark clouds,” elaborates Lacour. “Convection moves around the clouds of silicate and iron particles, which disaggregate and rain down into the interior. This paints a picture of a dynamic atmosphere of a giant exoplanet at birth, undergoing complex physical and chemical processes.”
This result builds on GRAVITY’s string of impressive discoveries, which have included breakthroughs such as last year’s observation of gas swirling at 30% of the speed of light just outside the event horizon of the massive Black Hole in the Galactic Centre. It also adds a new way of observing exoplanets to the already extensive arsenal of methods available to ESO’s telescopes and instruments — paving the way to many more impressive discoveries.
See the original release at https://www.eso.org/public/news/eso1905/
-- Forwarded by Karen Pollard.
12. Magnetic Star Mapped
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a so-called Zeeman-Doppler-Image (ZDI) of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Otherwise they are seen only as point sources, even in the largest telescopes and interferometers. This technique, referred to as Doppler imaging (DI) or Doppler tomography, requires a high-resolution spectrograph, usually a large telescope, lots of observing time, and nifty analysis software. Each atomic spectral line can be seen as a compressed one-dimensional “image” of the stellar surface, which, if the star rotates, becomes broadened by the Doppler effect. If a star has spots on its surface, just like our Sun has sunspots, the Doppler-broadened spectral line profiles will be selectively deformed. A time series of such spectral line profiles taken over a full stellar rotation can then be converted to a temperature (or brightness) image of the otherwise unresolved stellar surface, just like in medical brain tomography.
But PEPSI can go a major step further. Because its two polarimeters also feed polarized light to the spectrograph, PEPSI captures the otherwise hidden profile deformation due to the Zeeman effect. The Zeeman effect is the splitting and polarization of spectral lines due to an external magnetic field. Combined with the rotational Doppler-effect it allows the reconstruction of the star’s surface magnetic field geometry. The cartography in polarized light is thus called Zeeman-Doppler-Imaging or in short just ZDI.
In a dedicated observing run with PEPSI attached to the effectively 11.8m aperture LBT a team of AIP astronomers was able to obtain a unique time series of polarized high-resolution spectra of the rotating star II Pegasi (HD 224085). “II Peg has a rotation period of 6.7 days and is thus manageable with the LBT in terms of the required observing time”, says the PEPSI Principal Investigator (PI) and author of the II Peg study Professor Klaus Strassmeier from the Leibniz Institute for Astrophysics in Potsdam, Germany (AIP). “And with seven clear nights we were very lucky as well”, adds the PEPSI project scientist Ilya Ilyin.
The already complex polarized spectra were analysed with the special inverse mapping code iMap developed at the AIP. This showed that warm and cool starspots had opposite polarity. “The warm features had positive polarity on II Peg while most of the cool feature had negative or mixed polarity”, says iMap-PI Thorsten Carroll.
The spot distribution on II Peg has no direct analogy on the Sun. The individual spots found on this star are huge compared to the Sun, about thousand times larger than sunspots. “We explain the co-existing warm spots of II Peg due to heating by a shock front caused by the plasma flow between regions of different polarities”, concludes Strassmeier. "Both as a spectrograph and as a spectropolarimeter, PEPSI is unique in today's worldwide suite of astronomical instruments and will make significant contributions to stellar physics", adds Christian Veillet, LBT Observatory's Director. "The need to characterize the stars hosting exoplanets, as well as the planets themselves through transit observations, should also make PEPSI a sought-after instrument to the members of the LBT community."
For the original release, with several animations see
http://www.lbto.org/pepsi-pol-2019.html
Original publication in A&A
K. G. Strassmeier, T. A. Carroll, & I. V. Ilyin, Warm and cool starspots with opposite polarities. A high-resolution Zeeman-Doppler-Imaging study of II Pegasi with PEPSI, A&A, in press; arXiv:190211201S
-- Forwarded by Karen Pollard.
13. NASA to Test Asteroid Diversion
One way of preventing an asteroid from hitting us is to change its orbit slightly by speeding it up or slowing it down. That way it passes Earth's position a little ahead or behind Earth. NASA plans to try this by hitting a small asteroid with a self-navigating spacecraft, DART, to see how much its orbit is altered.
DART is a planetary defence test of one of the technologies for preventing the Earth impact of a hazardous asteroid: the kinetic impactor. DART’s primary objective is to demonstrate a kinetic impact on a small asteroid. The binary near-Earth asteroid (65803) Didymos is the target for DART. While Didymos’ primary body is approximately 800 meters across, its secondary body, or “moonlet”, is 150-meter wide which is more typical of the size of asteroids that could pose a more common hazard to Earth.
The DART spacecraft will achieve the kinetic impact by deliberately crashing itself into the moonlet at a speed of approximately 6 km/s, with the aid of an on-board camera and sophisticated autonomous navigation software. The collision will change the speed of the moonlet in its orbit around the main body by a fraction of one percent, enough to be measured using telescopes on Earth.
DART will be included in either a commercial or military launch to geosynchronous orbit between December 2020 and May 2021 and released. Using the NEXT-C ion thrust engine, DART will spiral out beyond the orbits of the geosynchronous satellites and the Moon to reach an escape point to depart the Earth-Moon system en route to Didymos.
The DART spacecraft will utilize the NASA Evolutionary Xenon Thruster – Commercial (NEXT-C) solar electric propulsion system as its primary in-space propulsion system. NEXT-C is the next generation system that is based on the Dawn spacecraft propulsion system and was developed at NASA’s Glenn Research Center in Cleveland, Ohio. By utilizing electric propulsion, DART is able to gain significant flexibility to the mission timeline and widen the launch window, as well as decrease the cost of the launch vehicle that gets the mission off Earth and into orbit.
The ion engine is powered by electricity from Roll Out Solar Arrays (ROSA). With the ROSA arrays fully deployed, DART measures 12.5 meters by 2.4 meters.
NASA’s DART spacecraft’s launch window range begins in late December 2020 and runs through to May 2021. It will intercept Didymos’ moonlet in early October 2022, when the Didymos system is within 11 million km of Earth, enabling observations by ground-based telescopes and planetary radar to measure the change in momentum imparted to the moonlet.
The Didymos system comprises a primary body is about 800 meters in diameter with the moonlet is approximately 150 meters across. They are separated by just over a kilometre. The primary body rotates once every 2.26 hours while the tidally locked moonlet revolves about the primary once every 11.9 hours. Almost one-sixth of the known near-Earth asteroid (NEA) population are binary or multiple-body systems.
For the original item with many photos and diagrams see
https://www.nasa.gov/planetarydefense/dart
-- Forwarded by Karen Pollard.
14. Pitcairn Islands Newest Astro-Tourism Destination
The remote Pitcairn Islands group has become one of only 8 International Dark Sky Association (IDA) designated Dark Sky Sanctuaries in the world. Pitcairn’s Mata ki te Rangi - Eyes to the Sky International Dark Sky Sanctuary encompasses all 4 islands in the group, it is a designation that means everything in the world of night sky conservation and international astro-tourism. Additionally, the Pitcairn Islands Group is the first British Overseas Territory, and only island group in the world, to have been granted IDA Dark Sky Sanctuary status.
The Pitcairn Islands group first made news in the conservation world in 1988 when its largest island, Henderson, became a UNESCO World Heritage Site – securing protection of its 10 endemic plants and 4 land birds. More recently, in 2015, the United Kingdom declared the waters surrounding the Pitcairn Islands as the largest protected ocean area in the world. Today it remains the third largest Marine Protected Area in the world.
The Dark Sky Sanctuary announcement has strengthened Pitcairn’s commitment to protect one of the planet’s most remote and pristine multi-island environments for generations to come.
Located deep in the South Pacific, more than 500kms from its nearest populated neighbour, the Pitcairn Islands have amongst the world’s clearest oceans and night skies in the world. And Pitcairn Islands Tourism is launching its astro-tourism profile in a most appropriate way. On July 2nd, a total solar eclipse will cross uninhabited Oeno Island, one of group’s 4 islands, at 10:23 a.m. lasting for 2 minutes 51 seconds.
Pitcairn Travel Coordinator, Heather Menzies said, “The July eclipse is a unique opportunity to celebrate being the world’s newest Dark Sky Sanctuary. We’ve released an 8-day Total Solar Eclipse Voyage, which has already sold-out - though we’re accepting waitlist enquiries! The tour visits both Pitcairn and Oeno Islands, landing at Oeno for the eclipse and over-nighting at Pitcairn to soak up the warm hospitality of the descendants of the Bounty mutineers. Passengers will also share in the island’s first Mata ki te Rangi - International Dark Sky Sanctuary community dinner.
2019 also marks the launch of Pitcairn’s new shipping service, offering 21 round-trips annually between Mangareva in French Polynesia and Pitcairn Island. This is up from 12 trips in 2018 providing visitors with greater access to Pitcairn than ever before. In addition, Pitcairn Islands Tourism has also released a unique 4-island Explorers Voyage in October 2019, which will visit all 4 islands in the Mata ki te Rangi International Dark Sky Sanctuary – the Explorers Voyage still has limited availability.
Located between New Zealand and Peru, Pitcairn is home to the descendants of the Bounty mutineers. It is one of the most remote and undiscovered tourism destinations in the world. This new “International Dark Sky Sanctuary” designation will provide visitors with yet another compelling reason to visit this fascinating and remote destination.
For more information see www.visitpitcairn.pn
-- Press release from Pitcairn Islands Tourism Marketing.
15. 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 treasurer@rasnz.co.nz or
by completing the online application form found at
http://rasnz.org.nz/rasnz/membership-application
Basic membership for the 2018 year starts at $40 for an ordinary
member, which includes an electronic subscription to our journal
'Southern Stars'.
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. Full details are set down in
the RASNZ By-Laws, Section J.
For an application form contact the RASNZ Executive Secretary,
secretary@rasnz.org.nz
17. May Newsletter Will be Late
Due to the Conference, and the Newsletter editor's travels around it, the May Newsletter will be circulated on or after May 27.
18. Quote
"The black hole teaches us that space can be crumpled like a piece of paper into an infinitesimal dot, that time can be extinguished like a blown-out flame, and that the laws of physics that we regard as 'sacred', as immutable, are anything but." -- John Wheeler quoted in Marcus Chown's 'The Ascent of Gravity', Weidenfeld & Nicolson, 2017.
Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
eNewsletter: No. 220, 20 April 2019 Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website www.rasnz.org.nz in their own newsletters provided an acknowledgement of the source is also included.
Contents
1. Black Hole Imaged
2. Roy Kerr named FRS
3. 2019 RASNZ Conference - New Plymouth
4. The Solar System in May
5. Variable Stars South News
6. New Zealand Starlight Conference, October 2019
7. Astronomy for Equity, Diversity and Inclusion
8. 2020 Conference and RASNZ Centenary
9. NZ Post Stamp Issue: New Zealand Space Pioneers
10. LIGO-VIRGO On-Line
11. Exoplanet Directly Observed
12. Magnetic star mapped
13. NASA to Test Asteroid Diversion
14. Pitcairn Islands Newest Astro-Tourism Destination
15. How to Join the RASNZ
16. Kingdon-Tomlinson Fund
17. May Newsletter Will be Late
18. Quote
1. Black Hole Imaged
On April 10 an international collaboration announced that they had imaged a black hole or, more accurately, the shadow of a black hole.
The breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the centre of Messier 87, a massive galaxy 55 million light-years away in the Virgo galaxy cluster. The black hole has a mass 6.5 billion times that of the Sun.
The black hole was seen by combining the output of many widely-spaced radio telescopes in a technique called very-long-baseline interferometry (VLBI). The effect is to form one huge, Earth-size telescope observing at a wavelength of 1.3 mm. VLBI allowed the Event Horizon Telescope (EHT), as the consortium is called, to achieve an angular resolution of 20 micro-arcseconds, about 37mm at the Moon's distance.
The EHT offers scientists a new way to study the most extreme objects in the Universe predicted by Einstein’s general relativity. This is being done in the centenary year of the historic experiment that first confirmed the theory: the measurements of the bending of starlight by the Sun from photos taken during a total solar eclipse.
Black holes are cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping space-time and superheating any surrounding material.
"If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow — something predicted by Einstein’s general relativity that we’ve never seen before," explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. "This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and has allowed us to measure the enormous mass of M87’s black hole."
Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region — the black hole’s shadow — that persisted over multiple independent EHT observations. The shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across.
Creating the EHT was a formidable challenge which required upgrading and connecting a worldwide network of eight pre-existing telescopes deployed at a variety of challenging high-altitude sites. These locations included volcanoes in Hawai`i and Mexico, mountains in Arizona and the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.
The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope.
The East Asian Observatory (EAO) partner on the EHT project represents the participation of many regions in Asia, including China, Japan, Korea, Taiwan, Vietnam, Thailand, Malaysia, India and Indonesia.
Although the telescopes are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. The data was flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration
Adapted from European Southern Observatory release eso1907.
See also https://eventhorizontelescope.org/
Sergei Gulyaev of AUT gave a radio astronomer's perspective on the imaging in a National Radio Morning Report interview at
https://www.radionz.co.nz/national/programmes/morningreport/audio/2018690507/black-hole-image-a-mt-everest-for-nz-science
David Wiltshire of Canterbury University talked about the imaging from a relativity and cosmological viewpoint at https://www.radionz.co.nz/national/programmes/lately/audio/2018690646/roy-kerr-s-black-hole-theory-proven-right
2. Roy Kerr named FRS
University of Canterbury Distinguished Professor Roy Kerr FRSNZ CRSNZ has been named a Fellow of The Royal Society, London. Last week his revolutionary 56-year-old solution of Einstein's equations that describe rotating black holes was proven correct with the first black hole image.
Minimal details at https://royalsociety.org/news/2019/04/royal-society-announces-2019-fellows/
3. 2019 RASNZ Conference - New Plymouth
The annual RASNZ conference will be held in New Plymouth from Friday 17th until Sunday 19th May 2019.
You will find an announcement on RASNZ home page www.rasnz.org.nz - click on the "Read more" button to go to the conference information page. There you will find links to the on-line conference registration form, the online paper submission form, the conference brochure and a downloadable registration form (for those who want to fill out a form manually). Immediately following the conference in New Plymouth the 13th Trans-Tasman Symposium on Occultations will run from Monday to mid-day Tuesday.
For those who wish to take advantage of the special conference rate for accommodation at the venue (the Devon Hotel) the promo code is RASNZ2019. The conference brochure, available for download on the RASNZ's conference webpage has been updated with this information.
The RASNZ Conference webpage is updated with abstracts of papers as they are accepted so keep an eye on that page to see what will be on offer.
-- Glen Rowe, Chair, Standing Conference Committee.
4. The Solar System in May
Dates and times shown are NZST (UT + 12 hours). Rise and Set times are for Wellington. They will vary by a few minutes elsewhere in NZ. Data is adapted from that shown by GUIDE 9.
THE SUN and PLANETS in MAY, Rise & Set, Mag. & Cons.
May 1 NZST May 31 NZST
Mag Cons Rise Set Mag Cons Rise Set
SUN -26.7 Ari 7.04am 5.30pm -26.7 Tau 7.33am 5.03pm
Merc 0.8 Psc 5.20am 4.49pm -0.3 Tau 8.34am 5.37pm
Venus -3.9 Psc 4.43am 4.26pm -3.8 Ari 5.50am 4.01pm
Mars 1.5 Tau 10.29am 7.36pm .1.6 Gem 9.57am 7.02pm
Jup -2.2 Oph 7.45pm 10.47am -2.4 Oph 5.37pm 8.35am
Saturn 0.6 Sgr 9.46pm 12.37pm 0.5 Sgr 7.44pm 10.37am
Uranu 5.9 Ari 6.25am 5.07pm 5.9 Ari 4.35am 3.13pm
Nep 8.0 Aqr 2.36am 3.24pm 7.9 Aqr 12.41am 1.28pm
Pluto 14.5 Sgr 9.56am 12.50pm 14.5 Sgr 7.57pm 10.51am
May 1 NZST May 31 NZST
Twilights morning evening morning evening
Civil: start 6.39am, end 5.57pm start 7.05am, end 5.32pm
Nautical: start 6.06am, end 6.30pm start 6.31am, end 6.06pm
Astro: start 5.34am, end 7.02pm start 5.57am, end 6.39pm
MAY PHASES OF THE MOON, times NZST (& UT)
New moon: May 5 at 10.45am (May 4, 22:45 UT)
First quarter: May 12 at 1.12pm (01:12 UT)
Full Moon: May 19 at 9.11am (May 18, 21:11 UT)
Last quarter May 27 at 4.34am (May, 26 16:34 UT)
PLANETS in May
MERCURY will be visible about an hour before sunrise for the first week of May, a few degrees to the lower right of Venus. The moon, as a very thin crescent will be some 6° above Mercury on the morning of May 3.
Mercury is at superior conjunction on the 21st, so too close to the Sun for observation for the last three weeks of May.
VENUS drops further behind Mercury during May and remains a morning object. It will be readily visible fairly low in the morning twilight. The crescent moon will be to the right of and a little lower then Venus on the morning of May 3.
MARS is the one planet visible in the early evening. It sets about 2 hours after the Sun all month, a low object to the northwest as the sky darkens. On the 8th the crescent moon will be 3.5° above Mars
JUPITER will be easily visible to the east in the second half of the evening during May. It is also visible to the north and then west in the morning. The near full moon is just under 2° from Jupiter on the morning of May 21.
SATURN rises early evening by the end of May, so will readily be visible to the east an hour or two later. This month's occultation by the moon is visible from the south Indian Ocean.
URANUS begins to move up into the morning sky during May. It is one degree to the left of Venus on the morning of May 19.
NEPTUNE is also a morning object. It will be about 3° to the lower left of the moon on the morning of June 28, with the moon just past last quarter
PLUTO is about 3° from Saturn all month.
BRIGHTEST ASTEROIDS in MAY, mag. const. time of transit
MAY 1 NZDT MAY 31 NZST
Mag Cons transit Mag Cons transit
(1) Ceres 7.6 Oph 2.32am 7.0 Sco 12.08am
(2) Pallas 8.3 Boo 11.25pm 8.9 Com 9.15pm
(4) Vesta 8.2 Cet 10.39pm 8.3 Psc 9.30am
CERES rises at 7.24 pm on the 1st and 5 pm on the 31st, being about 12° from Jupiter. The near full moon will be just under 4° to the upper left of Ceres on the evening of May 19 and less than 1° to the left of the asteroid the following morning. Ceres is at opposition on May 28.
PALLAS rises at 6.45 pm on May 1 when it will be 9° from Arcturus. By the end of May it will rise at 4.40 pm, shortly before sunset.
VESTA will be 3.3° to the left of Venus on the morning of May 2, with the moon some 9° above the two. The following morning the three will form a triangle with the moon 3° below Vesta and to the lower right of Venus. Vesta will rise at 3.45 am on the 31st
-- Brian Loader
5. Variable Stars South News
AAVSO Alert U Scorpi
Frequent monitoring is requested of the recurrent nova U Scorpii over the next year or so to discover the upcoming very-fast eruption. The predicted outburst is for the year 2020.0±0.7. The eruption is likely within the next year, but it could well go off tonight. For details of procedure to advise an outburst refer to AAVSO Alert 664. Visual and CCD/DSLR observers are requested to observe as frequently as possible.
The importance of this is supported by the following data: rise to maximum outburst about 6 h; time to fade to < mag 10.5 2.6 days.
For details see https://www.aavso.org/aavso-alert-notice-664
AAVSO On-Line Courses
Upcoming AAVSO CHOICE courses:: How to use VStar (May 6 - 31); NEW! Observing and Counting Sunspots (June 3 - 14); Developing a Visual Observing Program (August 5 - 30). From AAVSO Monthly Communication April 2019.
-- Alan Baldwin
6. New Zealand Starlight Conference, October 2019
We are planning a conference on dark skies, combatting light pollution and star gazing to be held at Lake Tekapo, in the world’s largest International Dark Sky Reserve. See http://starlightconference.org/
The dates will be 6 pm on Sunday 20 October 2019 to 4.30 pm on Wednesday 23 October 2019.
The New Zealand Starlight Conference is supported by the International Dark Sky Association and hosted by the Aoraki Mackenzie International Dark Sky Reserve Board.
More details will be posted on the website above in the coming months. Members of RASNZ and affiliated societies will be most welcome as participants.
We hope to see many RASNZ members at the conference.
-- John Hearnshaw, Chair of AMIDSR Board.
7. Astronomy for Equity, Diversity and Inclusion
Grant applications are open for International Astronomical Union Symposium IAUS358 on Astronomy for Equity, Diversity and Inclusion
The International Astronomical Union (IAU) and the National Astronomical Observatory of Japan (NAOJ) will host the first IAU Symposium on "Astronomy for Equity, Diversity and Inclusion -- a roadmap to action within the framework of IAU centennial anniversary" in Tokyo, Japan, from 12-15 November, 2019. IAU grant applications are now open. Please pre-register, submit your abstract and application by 15 June 2019.
Relevant information is at:
Official Website: https://iau-oao.nao.ac.jp/iaus358/
Early Registration: https://iau-oao.nao.ac.jp/iaus358/registration/
Abstract Submission: https://iau-oao.nao.ac.jp/iaus358/abstract-submission/
Grant Application: https://iau-oao.nao.ac.jp/iaus358/iau-travel-grants/
Contact: iaus358contact@prcml.mtk.nao.ac.jp
Important Note: This will be a symposium strongly focused on discussions among participants and interactions between speakers and participants. To optimize the dialogues during the symposium and accommodate all needs, the organization has a participant limit. We therefore recommend all interested to secure an early registration soon.
-- Lina Canas, Assistant Outreach Coordinator, Office for Astronomy Outreach, International Astronomical Union. Passed along by the Royal Society of NZ.
8. 2020 Conference and RASNZ Centenary
The 2020 Conference will be held 8-10 May at Wellington with the Wharewaka Function Centre the venue (near the Michael Fowler Centre) in downtown Wellington. The Wellington Astronomical Society is hosting this conference.
2020 marks a significant milestone in the life of the Society as it was founded in November 1920 with 75 members.
The SCC invites ideas from members how the Society might commemorate its centenary at next year’s conference. Please send your suggestions to the SCC at conference@rasnz.org.nz.
-- Glen Rowe, Chair, Standing Conference Committee
9. NZ Post Stamp Issue: New Zealand Space Pioneers
Immersed in a clear, unpolluted southern sky, from New Zealand we have more stars and galaxies accessible to the naked eye than in most parts of the Northern Hemisphere. It is not surprising then that for most of New Zealand’s history, the lines between professional and amateur astronomers have been blurred. It is in this spirit that New Zealanders have helped to advance the world’s knowledge about space and space sciences.
For details see
https://stamps.nzpost.co.nz/new-zealand/2019/space-pioneers
Pre order now for 1 May 2019.
10. LIGO-VIRGO On-Line
The LIGO Scientific Collaboration and the Virgo Collaboration report:
Our third observing run ("O3") began as scheduled on 2019 April 1 at 15:00 UTC. At that time the LIGO Hanford, LIGO Livingston, and Virgo
Observatories transitioned from engineering and commissioning to
observing. All three detectors are operating at good sensitivity and
stability. We are analyzing data in low latency and processing candidate
transient events automatically.
As of April 2 20:00 UTC, we have configured our low-latency analysis
pipeline to send public alerts for significant gravitational-wave
transient candidates that are detected in coincidence across two or more
gravitational-wave detectors.
Automated Preliminary GCN Notices will be sent immediately without any
human intervention. Shortly afterward, they will be vetted by an LSC/Virgo rapid response team and either confirmed with an Initial GCN Notice and Circular, or withdrawn with a Retraction.
Retraction notices may be issued more frequently over the next few weeks
as our understanding of the instrumental background improves.
For further information about vetting procedures, analysis methodology,
and the contents of LIGO/Virgo public alerts, refer to the LIGO/Virgo
Public Alerts User Guide
This marks the beginning of the era of public alerts for the field of
gravitational-wave astronomy.
-- Leo Singer at GSFC/iPTF in GCN CIRCULAR No. 24045
11. Exoplanet Directly Observed
The GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI) has made the first direct observation of an exoplanet using optical interferometry.
This method revealed a complex exoplanetary atmosphere with clouds of iron and silicates swirling in a planet-wide storm. The technique presents unique possibilities for characterising many of the exoplanets known today.
This result was announced today in a letter in the journal Astronomy and Astrophysics by the GRAVITY Collaboration, in which they present observations of the exoplanet HR8799e using optical interferometry. The exoplanet was discovered in 2010 orbiting the young main-sequence star HR8799, which lies around 129 light-years from Earth in the constellation of Pegasus.
Today’s result, which reveals new characteristics of HR8799e, required an instrument with very high resolution and sensitivity. GRAVITY can use ESO’s VLT’s four 8.2-metre unit telescopes to work together to mimic a single larger telescope using a technique known as interferometry. This creates a super-telescope — the VLTI — that collects and precisely disentangles the light from HR8799e’s atmosphere and the light from its parent star.
HR8799e is a ‘super-Jupiter’, a world unlike any found in our Solar System, that is both more massive and much younger than any planet orbiting the Sun. At only 30 million years old, this baby exoplanet is young enough to give scientists a window onto the formation of planets and planetary systems. The exoplanet is thoroughly inhospitable — leftover energy from its formation and a powerful greenhouse effect heat HR8799e to a hostile temperature of roughly 1000 °C.
This is the first time that optical interferometry has been used to reveal details of an exoplanet, and the new technique furnished an exquisitely detailed spectrum of unprecedented quality — ten times more detailed than earlier observations. The team’s measurements were able to reveal the composition of HR8799e’s atmosphere — which contained some surprises.
“Our analysis showed that HR8799e has an atmosphere containing far more carbon monoxide than methane — something not expected from equilibrium chemistry,” explains team leader Sylvestre Lacour researcher CNRS at the Observatoire de Paris - PSL and the Max Planck Institute for Extraterrestrial Physics. “We can best explain this surprising result with high vertical winds within the atmosphere preventing the carbon monoxide from reacting with hydrogen to form methane.”
The team found that the atmosphere also contains clouds of iron and silicate dust. When combined with the excess of carbon monoxide, this suggests that HR8799e’s atmosphere is engaged in an enormous and violent storm.
“Our observations suggest a ball of gas illuminated from the interior, with rays of warm light swirling through stormy patches of dark clouds,” elaborates Lacour. “Convection moves around the clouds of silicate and iron particles, which disaggregate and rain down into the interior. This paints a picture of a dynamic atmosphere of a giant exoplanet at birth, undergoing complex physical and chemical processes.”
This result builds on GRAVITY’s string of impressive discoveries, which have included breakthroughs such as last year’s observation of gas swirling at 30% of the speed of light just outside the event horizon of the massive Black Hole in the Galactic Centre. It also adds a new way of observing exoplanets to the already extensive arsenal of methods available to ESO’s telescopes and instruments — paving the way to many more impressive discoveries.
See the original release at https://www.eso.org/public/news/eso1905/
-- Forwarded by Karen Pollard.
12. Magnetic Star Mapped
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a so-called Zeeman-Doppler-Image (ZDI) of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Otherwise they are seen only as point sources, even in the largest telescopes and interferometers. This technique, referred to as Doppler imaging (DI) or Doppler tomography, requires a high-resolution spectrograph, usually a large telescope, lots of observing time, and nifty analysis software. Each atomic spectral line can be seen as a compressed one-dimensional “image” of the stellar surface, which, if the star rotates, becomes broadened by the Doppler effect. If a star has spots on its surface, just like our Sun has sunspots, the Doppler-broadened spectral line profiles will be selectively deformed. A time series of such spectral line profiles taken over a full stellar rotation can then be converted to a temperature (or brightness) image of the otherwise unresolved stellar surface, just like in medical brain tomography.
But PEPSI can go a major step further. Because its two polarimeters also feed polarized light to the spectrograph, PEPSI captures the otherwise hidden profile deformation due to the Zeeman effect. The Zeeman effect is the splitting and polarization of spectral lines due to an external magnetic field. Combined with the rotational Doppler-effect it allows the reconstruction of the star’s surface magnetic field geometry. The cartography in polarized light is thus called Zeeman-Doppler-Imaging or in short just ZDI.
In a dedicated observing run with PEPSI attached to the effectively 11.8m aperture LBT a team of AIP astronomers was able to obtain a unique time series of polarized high-resolution spectra of the rotating star II Pegasi (HD 224085). “II Peg has a rotation period of 6.7 days and is thus manageable with the LBT in terms of the required observing time”, says the PEPSI Principal Investigator (PI) and author of the II Peg study Professor Klaus Strassmeier from the Leibniz Institute for Astrophysics in Potsdam, Germany (AIP). “And with seven clear nights we were very lucky as well”, adds the PEPSI project scientist Ilya Ilyin.
The already complex polarized spectra were analysed with the special inverse mapping code iMap developed at the AIP. This showed that warm and cool starspots had opposite polarity. “The warm features had positive polarity on II Peg while most of the cool feature had negative or mixed polarity”, says iMap-PI Thorsten Carroll.
The spot distribution on II Peg has no direct analogy on the Sun. The individual spots found on this star are huge compared to the Sun, about thousand times larger than sunspots. “We explain the co-existing warm spots of II Peg due to heating by a shock front caused by the plasma flow between regions of different polarities”, concludes Strassmeier. "Both as a spectrograph and as a spectropolarimeter, PEPSI is unique in today's worldwide suite of astronomical instruments and will make significant contributions to stellar physics", adds Christian Veillet, LBT Observatory's Director. "The need to characterize the stars hosting exoplanets, as well as the planets themselves through transit observations, should also make PEPSI a sought-after instrument to the members of the LBT community."
For the original release, with several animations see
http://www.lbto.org/pepsi-pol-2019.html
Original publication in A&A
K. G. Strassmeier, T. A. Carroll, & I. V. Ilyin, Warm and cool starspots with opposite polarities. A high-resolution Zeeman-Doppler-Imaging study of II Pegasi with PEPSI, A&A, in press; arXiv:190211201S
-- Forwarded by Karen Pollard.
13. NASA to Test Asteroid Diversion
One way of preventing an asteroid from hitting us is to change its orbit slightly by speeding it up or slowing it down. That way it passes Earth's position a little ahead or behind Earth. NASA plans to try this by hitting a small asteroid with a self-navigating spacecraft, DART, to see how much its orbit is altered.
DART is a planetary defence test of one of the technologies for preventing the Earth impact of a hazardous asteroid: the kinetic impactor. DART’s primary objective is to demonstrate a kinetic impact on a small asteroid. The binary near-Earth asteroid (65803) Didymos is the target for DART. While Didymos’ primary body is approximately 800 meters across, its secondary body, or “moonlet”, is 150-meter wide which is more typical of the size of asteroids that could pose a more common hazard to Earth.
The DART spacecraft will achieve the kinetic impact by deliberately crashing itself into the moonlet at a speed of approximately 6 km/s, with the aid of an on-board camera and sophisticated autonomous navigation software. The collision will change the speed of the moonlet in its orbit around the main body by a fraction of one percent, enough to be measured using telescopes on Earth.
DART will be included in either a commercial or military launch to geosynchronous orbit between December 2020 and May 2021 and released. Using the NEXT-C ion thrust engine, DART will spiral out beyond the orbits of the geosynchronous satellites and the Moon to reach an escape point to depart the Earth-Moon system en route to Didymos.
The DART spacecraft will utilize the NASA Evolutionary Xenon Thruster – Commercial (NEXT-C) solar electric propulsion system as its primary in-space propulsion system. NEXT-C is the next generation system that is based on the Dawn spacecraft propulsion system and was developed at NASA’s Glenn Research Center in Cleveland, Ohio. By utilizing electric propulsion, DART is able to gain significant flexibility to the mission timeline and widen the launch window, as well as decrease the cost of the launch vehicle that gets the mission off Earth and into orbit.
The ion engine is powered by electricity from Roll Out Solar Arrays (ROSA). With the ROSA arrays fully deployed, DART measures 12.5 meters by 2.4 meters.
NASA’s DART spacecraft’s launch window range begins in late December 2020 and runs through to May 2021. It will intercept Didymos’ moonlet in early October 2022, when the Didymos system is within 11 million km of Earth, enabling observations by ground-based telescopes and planetary radar to measure the change in momentum imparted to the moonlet.
The Didymos system comprises a primary body is about 800 meters in diameter with the moonlet is approximately 150 meters across. They are separated by just over a kilometre. The primary body rotates once every 2.26 hours while the tidally locked moonlet revolves about the primary once every 11.9 hours. Almost one-sixth of the known near-Earth asteroid (NEA) population are binary or multiple-body systems.
For the original item with many photos and diagrams see
https://www.nasa.gov/planetarydefense/dart
-- Forwarded by Karen Pollard.
14. Pitcairn Islands Newest Astro-Tourism Destination
The remote Pitcairn Islands group has become one of only 8 International Dark Sky Association (IDA) designated Dark Sky Sanctuaries in the world. Pitcairn’s Mata ki te Rangi - Eyes to the Sky International Dark Sky Sanctuary encompasses all 4 islands in the group, it is a designation that means everything in the world of night sky conservation and international astro-tourism. Additionally, the Pitcairn Islands Group is the first British Overseas Territory, and only island group in the world, to have been granted IDA Dark Sky Sanctuary status.
The Pitcairn Islands group first made news in the conservation world in 1988 when its largest island, Henderson, became a UNESCO World Heritage Site – securing protection of its 10 endemic plants and 4 land birds. More recently, in 2015, the United Kingdom declared the waters surrounding the Pitcairn Islands as the largest protected ocean area in the world. Today it remains the third largest Marine Protected Area in the world.
The Dark Sky Sanctuary announcement has strengthened Pitcairn’s commitment to protect one of the planet’s most remote and pristine multi-island environments for generations to come.
Located deep in the South Pacific, more than 500kms from its nearest populated neighbour, the Pitcairn Islands have amongst the world’s clearest oceans and night skies in the world. And Pitcairn Islands Tourism is launching its astro-tourism profile in a most appropriate way. On July 2nd, a total solar eclipse will cross uninhabited Oeno Island, one of group’s 4 islands, at 10:23 a.m. lasting for 2 minutes 51 seconds.
Pitcairn Travel Coordinator, Heather Menzies said, “The July eclipse is a unique opportunity to celebrate being the world’s newest Dark Sky Sanctuary. We’ve released an 8-day Total Solar Eclipse Voyage, which has already sold-out - though we’re accepting waitlist enquiries! The tour visits both Pitcairn and Oeno Islands, landing at Oeno for the eclipse and over-nighting at Pitcairn to soak up the warm hospitality of the descendants of the Bounty mutineers. Passengers will also share in the island’s first Mata ki te Rangi - International Dark Sky Sanctuary community dinner.
2019 also marks the launch of Pitcairn’s new shipping service, offering 21 round-trips annually between Mangareva in French Polynesia and Pitcairn Island. This is up from 12 trips in 2018 providing visitors with greater access to Pitcairn than ever before. In addition, Pitcairn Islands Tourism has also released a unique 4-island Explorers Voyage in October 2019, which will visit all 4 islands in the Mata ki te Rangi International Dark Sky Sanctuary – the Explorers Voyage still has limited availability.
Located between New Zealand and Peru, Pitcairn is home to the descendants of the Bounty mutineers. It is one of the most remote and undiscovered tourism destinations in the world. This new “International Dark Sky Sanctuary” designation will provide visitors with yet another compelling reason to visit this fascinating and remote destination.
For more information see www.visitpitcairn.pn
-- Press release from Pitcairn Islands Tourism Marketing.
15. 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 treasurer@rasnz.co.nz or
by completing the online application form found at
http://rasnz.org.nz/rasnz/membership-application
Basic membership for the 2018 year starts at $40 for an ordinary
member, which includes an electronic subscription to our journal
'Southern Stars'.
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. Full details are set down in
the RASNZ By-Laws, Section J.
For an application form contact the RASNZ Executive Secretary,
secretary@rasnz.org.nz
17. May Newsletter Will be Late
Due to the Conference, and the Newsletter editor's travels around it, the May Newsletter will be circulated on or after May 27.
18. Quote
"The black hole teaches us that space can be crumpled like a piece of paper into an infinitesimal dot, that time can be extinguished like a blown-out flame, and that the laws of physics that we regard as 'sacred', as immutable, are anything but." -- John Wheeler quoted in Marcus Chown's 'The Ascent of Gravity', Weidenfeld & Nicolson, 2017.
Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
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