April 2020 Newsletters and Research
Astronomy_News_20_04_2020
This months research Papers 20_04_2020
RASNZ_20_04_2020
Further links and discussion can be found at the groups/links below
Astronomy in New Zealand - Facebook
https://www.facebook.com/groups/5889909863/
Astronomy in New Zealand - Groups.io
https://groups.io/g/AstronomyNZ
Astronomy in Wellington
https://www.facebook.com/groups/11451597655/
Blogger Posts
http://laintal.blogspot.com/
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Research papers
An interstellar origin for high-inclination Centaurs
https://arxiv.org/abs/2004.10510
The multi-planet system TOI-421 A warm Neptune
https://arxiv.org/abs/2004.10095
Searching for the near infrared counterpart of Proxima c
https://arxiv.org/abs/2004.06685
Strong Near-Infrared Spectral Variability of the Young Cloudy L Dwarf Companion VHS J1256-1257 b
https://arxiv.org/abs/2004.05170
Habitability is a continuous property of nature
https://arxiv.org/abs/2004.06470
The Astrobiological Copernican Weak and Strong Limits for Extraterrestrial Intelligent Life
https://arxiv.org/abs/2004.03968
Radar evidence of subglacial liquid water on Mars
https://arxiv.org/abs/2004.04587
Detectability of Life Using Oxygen on Pelagic Planets and Water Worlds
https://arxiv.org/abs/2004.03631
Global Mapping of the Surface Composition on an Exo-Earth using Color Variability
https://arxiv.org/abs/2004.03931
an astrometric calibration field for high-contrast imagers in Baade's Window
https://arxiv.org/abs/2004.02923
Atmospheric convection plays a key role in the climate of tidally-locked terrestrial exoplanets
https://arxiv.org/abs/2004.03007
The effect of high nitrogen pressures on the habitable zone and an appraisal of greenhouse states
https://arxiv.org/abs/2004.00229
Outstanding Challenges of Exoplanet Atmospheric Retrievals
https://arxiv.org/abs/2003.14311
Focal Plane Wavefront Sensing with the FAST TGV Coronagraph
https://arxiv.org/abs/2003.13692
Salty Oceans in Low Mass Habitable Planets and Global Climate Evolution
https://arxiv.org/abs/2003.13107
Stellar Driven Evolution of Hydrogen-Dominated Atmospheres
https://arxiv.org/abs/2003.13412
A kinematically hot population of young stars in the solar neighbourhood
https://arxiv.org/abs/2003.13369
The Habitability of Large Elliptical Galaxies
https://arxiv.org/abs/2003.13643
Uranian Satellite Formation by Evolution of a Water Vapor Disk
https://arxiv.org/abs/2003.13582
From Super-Earths to Mini-Neptunes
https://arxiv.org/abs/2003.13348
Earth-size planet formation in the habitable zone of circumbinary stars
https://arxiv.org/abs/2003.11682
Habitability of polar regions in tidally locked extrasolar planet near the M-Dwarf stars
https://arxiv.org/abs/2003.11732
Explaining the Cold Temperatures Retrieved from Transmission Spectra of Exoplanet Atmospheres
https://arxiv.org/abs/2003.11548
Atmospheric evolution from noble gas and Nitrogen on Earth Mars & Venus
https://arxiv.org/abs/2003.11431
An information theoretic framework for classifying exoplanetary system architectures
https://arxiv.org/abs/2003.11098
Delivery of water and volatiles to the terrestrial planets and the Moon
https://arxiv.org/abs/2003.09982
Human wealth evolution trends and fluctuations
https://arxiv.org/abs/2003.11502
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Interesting News items
Earth-Size, Habitable Zone Planet Found Hidden in Early NASA Kepler Data
http://astrobiology.com/2020/04/earth-size-habitable-zone-planet-found-hidden-in-early-nasa-kepler-data.html
Earth-Size, Habitable-Zone Planet Found Hidden in Early NASA Kepler Data
https://www.jpl.nasa.gov/news/news.php?feature=7639
Interesting Earth-sized Planet Turns Up in Kepler Data
https://www.centauri-dreams.org/2020/04/16/kepler-1649c-interesting-earth-sized-planet-turns-up-in-kepler-data/
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Updates from Andrew B,
Mars Science Laboratory Curiosity.
Sols 2,723 & 2,724. Saturday 4th & Sunday 5th April 2020.
LMST = Local Mars Standard Time in Gale Crater.
Sol 2,723. The larger and inner Mars moon Phobos passed in front of the Sun as seen from MSL Curiosity, using the 100 mm MastCam, Mast Camera. Phobos was passing from bottom to top.
The Sun & Phobos appeared in front of the constellation of Taurus the Bull, between the horns, between the stars Al Nath / Beta Tauri and Tianguan / Zeta Tauri. Just north of M1, The Crab Nebula.
Mars was 220.5 million KM / 137.1 million miles from the Sun and Phobos was only 6,844 KM / 4,253 miles away from MSL Curiosity during this observation.
Phobos is only 27 KM by 22 KM by 18 KM / 17 by 14 by 11 miles in size, orbits Mars at a mean distance of 9,376 KM / 5,822 miles once every 7 hours and 22 minutes. Phobos appears to have a density of 1.88 g/cm3, so likely to be a rubble pile held together by gravity.
Phobos experiences a wide range of surface temperatures from a maximum of minus 4 Celsius / 25 Fahrenheit or 269 Kelvin to a minimum of minus 112 Celsius / minus 170 Fahrenheit or 161 Kelvin.
Phobos orbits Mars once every 7 hours and 22 minutes, where as Mars rotates on it's axis once every 24 hours and 37 minutes (very similar to Earth's 23 hours and 56 minutes), meaning that Phobos is lapping the rotation of Mars. Therefore to an observer on the surface, Phobos rises in the west and sets in the east. The Sun and other astronomical objects on Mars rise in the east and set in the west as on Earth. Phobos crosses the sky from west to east in 4 hours & 14 minutes then sets for 11 hours & six minutes.
Sol 2,724. A stunning Navigation Camera shot showing the Earth in the evening Martian twilight as the Martian evening star. The Earth appeared in front of the constellation of Cancer the Crab, the Earth very bright at magnitude minus 1.88. The Earth was 214.2 million KM / 133.1 million miles away. I have made an annotated version.
In theory the planet Venus and the stars Castor / Alpha Geminorum and Pollux / Beta Geminorum should be visible. Perhaps a professionally tidied up version will show all of these.
MSL Curisosty has climbed 465 metres / 1,526 feet since landing from a point 18 metres / 59 feet below the mean level of the Gale Crater floor, so is 483 metres / 1,585 feet above the mean floor of Gale Crater. Has also driven 24.051 KM / 14.944 miles since landing.
MSL Curiosity was climbing the 5,500 metre / 18,050 foot tall Aeolis Mons, at the inside the 4,850 metre / 15,900 foot deep and 154 KM / 96 mile wide Gale Crater, within the Aeolis Quadrangle on Mars.
MSL Curiosity remains in superb shape and continues to operate flawlessly.
The afternoon maximum temperture here was a very warm for martian standards minus 6 Celsius / 23 Fahrenheit with a sunrise low of a very mild minus 68 Celsius / minus 90 Fahrenheit. Atmospheric pressure was 7.2 mb. Winds light, sunny by day, clear at night.
100 mm MastCam. Mast Camera.
Navigation Cameras.
Text: Andrew R Brown.
NASA / JPL / Malin Space Science Systems. Mars Science Laboratory Curiosity.
Tuesday 7th April 2020.
Ashford, Kent, United Kingdom.
Venus, with a diameter of 12,104 KM / 7,521 miles and a mass of 4,867.5 billion trillion tons (4,867.5 followed by, twenty zeros tons) was 90.15 million KM / 56.02 million miles from Earth.
Our 3,481 KM / 2,163 mile wide, 74.2 billion trillion ton (74.2 followed by twenty zeros tons) natural satellite the Moon, taken just now. The Pink Full Moon was 356,915 KM / 221,777 miles away from Earth.
Venus appeared close to The Pleiades / Seven Sisters, aka M45. M45 / The Pleiades also known as The Seven Sisters are approximately 385 light years away from the Solar System, so the light we are seeing in 2020 left the heart of the cluster in 1635. The cluster of hot blue B Type stars are thought to be only approximately 100 million years old, barely 2.2% the age of our Solar System. The dinosaurs were beginning to enter their final age on Earth & was about the middle of the Cretaceous period on Earth when the Pleiades formed. The Pleiades may be related to the Tucana – Horologium (a smattering of stars within the southern constellations of Tucana the Toucan and Horologium the Clock) group of similarly aged hot blue stars and their common motion in space as they orbit the centre of the Milky Way suggest a common origin and were once two parts of a much larger cluster. Some of the further stars are about 444 Light years away, light we are seeing in 2020, left them in the year 1591.
The centre of The Pleiades / M45 were about 38.914 million times further away than Venus.
Also got Venus with the Pleiades with the head of Taurus the Bull with the V shaped Hyades cluster, the dying red giant star Aldebaran / Alpha Tauri & just to the left of M45, The Pleiades / Seven Sisters.
The > shape pattern is the central 16 light years of the entire cluster and the centre of the Hyades is approximately 153 light years away from our Solar System, so we are seeing this portion of the cluster in 2020 around the year 1867.
The star at the top right at the end of the V is known as Ain / Epsilon Tauri. Ain / Epsilon Tauri is an ageing Orange Giant star entering the final stages of it's life. With a mass of 2.7 times that of our Sun, Ain / Epsilon Tauri although only approximately 526 million years old is already swelling up into gianthood. Helium in it's core has started to fuse into Oxygen and Carbon with the hydrogen fusing layer extending upwards towards the surface causing the star to swell up and it's surface temperature to cool, the fate of our own Sun in approx. 4 billion years time. Ain / Epsilon Tauri is approximately 12 times wider than the Sun or approx 1,310 times wider than the Earth.
Ain / Epsilon Tauri also has a large massive gas giant planet, some 7.8 times the mass of Jupiter or 2,480 times more massive than Earth. The giant planet orbits Ain / Epsilon Tauri once every 595 days at an average distance of 290 million KM / 180 million miles. This is a good example of a planet in orbit around a dying star.
Aldebaran / Alpha Tauri, the brightest star to the upper left at the end of the V is actually not related to the Hyades at all, but merely lies along the same direction from our viewpoint.
Aldebaran / Alpha Tauri, lies some 65 light years away from our solar system, so is a little less than half the distance to the Hyades. Aldebaran / Alpha Tauri is a dying orange giant star entering the final stages of it's life. With a mass of 1.7 times that of our Sun or about 566,000 times that of the Earth (our Sun has a mass of 332,946 Earths), Aldebaran / Alpha Tauri although only approximately 800 million years old is already swelling up into gianthood. Helium in it's core has started to fuse into Oxygen (free Oxygen created through thermonuclear reactions, not molecular oxygen created by plants through photosynthesis) and Carbon with the hydrogen fusing layer extending upwards towards the surface causing the star to swell up and it's surface temperature to cool, the fate of our own Sun in approximately 4 billion years time.
Aldebaran / Alpha Tauri is approx 44 times wider than the Sun or approximately 4,800 times wider than the Earth (our Sun is 109 times wider than the Earth). Aldebaran / Alpha Tauri is also a slow rotating star, taking 643 days or approx 1 year and 9 months to rotate once as against our Sun's 25 days.
Camera: Canon Powershot SX430 IS.
Taken by: Andrew R Brown.
Main Belt Asteroid / Protoplanet: 2 Pallas.
New images. Southern hemisphere left panel , northern hemisphere right panel.
2 Pallas was discovered on: Sunday 28th March 1802, by Heinrich Wilhelm Matthias Olbers, in Bremen, Germany.
Here is seen the gigantic Main Belt Asteroid 2 Pallas, imaged by the European Southern Observatory, Very Large Telescope / Spectro Polarimetric High-contrast Exoplanet REsearch instrument / SPHERE and the very capable very high resolution adaptive optics system.
Asteroid 2 Pallas is greyish in colour, is a type B, water rick carbon rich asteroid with a mean density of about 2.75 grammes per cubic centimetre and appears to be a solid, coherent object, not a rubble pile held together by gravity.
2 Pallas is 550 KM by 516 KM by 476 KM / 342 by 321 by 296 miles in size.
2 Pallas orbits the Sun once every 4 years, 8 months and 14 days at a mean distance of 416.1 million KM / 258.6 million miles. A very steeply inclined orbit of 34.82 degrees.
2 Pallas is extremely heavily cratered, possibly currently the most heavily cratered large body known, even more so than Main Belt asteroid / protoplanet 1 Ceres, the Jupiter moon Callisto, Saturn moons Rhea, Tethys and Mimas and the Uranus moons Umbriel and Oberon, other large, heavily cratered bodies seen in detail in the solar system.
There are 36 craters, covering 10% of 2 Pallas’s surface, in size between 30 KM to 120 KM / 19 miles to 75 miles wide. Part of this may be due to the strangely highly inclined orbit that 2 Pallas has around the Sun, this increases impact speeds with objects in more normal low inclination orbits to as high as 39,600 KPH / 24,606 MPH, which protoplanets / asteroids 1 Ceres & 4 Vesta do not experience such energetic impacts.
Also in the southern hemisphere, appears a brighter spot, to the left of a large crater with a domed floor, possibly an ice rich, epsom salt outcrop or upwelling much like that within the Occater Crater on protoplanet 1 Ceres.
2 Pallas rotates once every 7 hours & 49 minutes in a retrograde east to west direction.
Resolution. Approximately 18 KM / 11 miles.
Text: Andrew R Brown.
Image Credit: European Southern Observatory. ESO/M. Marsset et al./MISTRAL
Very Large Telescope / Spectro Polarimetric High-contrast Exoplanet REsearch instrument / SPHERE.
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Royal Astronomical Society of New Zealand
Royal Astronomical Society of New Zealand
eNewsletter: No. 232, 20 April 2020
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. Michele Bannister Awarded the 2020 Zeldovich Medal
2. Conference and AGM at Labour Weekend
3. Existing Registrations for 2020 Conference
4. Dark Sky Workshop - new date
5. The Solar System in May
6. Current Brightish Comets
7. 'Eye on the Sky' Video
8. New Zealand Astrophotography Competition - Closes September 21
9. Stargazers Getaway September 18-20
10. 14th Asia-Pacific Regional IAU Meeting Cancelled
11. Communicating Astronomy with the Public Conference
12. Fossil Shells Tell Cretaceous Day Length
13. Katherine Johnson Obituary
14. Neutron Star Size from Gravitational Waves
15. Mid-Size Black Hole Found?
16. How to Join the RASNZ
17. Quotes
1. Michele Bannister Awarded the 2020 Zeldovich Medal
Dr. Michele Bannister of Canterbury University has been awarded the 2020 Zeldovich Medal for the Committee on Space Research (COSPAR) Scientific Commission B.
The Zeldovich Medals are given to young scientists who have demonstrated excellence and achievement in their field of research. They are conferred by COSPAR and the Russian Academy of Sciences and honour the memory of the distinguished astrophysicist Academician Yakov B. Zeldovich.
Michele has been studying the small icy worlds beyond Neptune, co-discovering many of them with the 3.6-m Canada-France-Hawaii Telescope on Maunakea, Hawaii.
See https://cosparhq.cnes.fr/awards/zeldovich-medals/ but the website has not yet been updated with the 2020 award.
2. Conference and AGM at Labour Weekend
Dear RASNZ Members and 2020 Conference Delegates,
RASNZ Council has set the date for the 2020 AGM and Conference for Labour Weekend (23-25 October 2020). Please pencil these new dates into your calendar, noting that these new arrangements are themselves subject to further postponement depending on what restrictions remain on our activities at that time. Council will make further announcements relating to the AGM and Conference as developments arise.
For now, please stay safe within your isolation bubble!
Yours,
Nicholas Rattenbury, President, RASNZ
3. Existing Registrations for 2020 Conference
Those who paid their registration fees for the postponed conference but do not wish to attend the re-scheduled conference over Labour Weekend in October can request a full refund, by emailing the conference organisers (conference@rasnz.org.nz) and providing your bank account details.
Registrants wishing to attend the October Conference need take no action, your registration will remain on record for the rescheduled conference, there being no change to the registration fees.
-- Glen Rowe, Chair, Standing Conference Committee
4. Dark Sky Workshop - new date
A Dark Sky Workshop is planned to follow the re-scheduled RASNZ Conference as announced in the previous item. The workshop will be held, subject to any restrictions that may be in place at the time, on the morning of Monday 26 October2020 (Labour Day). Further details will be made available in due course.
-- Glen Rowe, Chair, Standing Conference Committee
5. 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 9.1
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 7.05am 5.29pm -26.7 Tau 7.33am 5.03pm
Merc -1.8 Ari 6.40am 5.20pm 0.1 Gem 9.30am 6.26pm
Venus -4.7 Tau 10.37am 7.10pm -4.2 Tau 8.10am 5.16pm
Mars 0.4 Cap 12.18am 2.22pm -0.0 Aqr 12.03am 1.18pm
Jup -2.4 Sgr 10.13pm 12.59pm -2.6 Sgr 8.14pm 11.01am
Sat 0.6 Cap 10.38pm 1.15pm 0.4 Cap 8.39pm 11.17am
Uran 5.9 Ari 6.45am 5.18pm 5.9 Ari 4.52am 3.21pm
Nep 7.9 Aqr 2.44am 3.26pm 7.9 Aqr 12.49am 1.30pm
Pluto 14.5 Sgr 10.00pm 12.56pm 14.5 Sgr 8.01pm 10.58am
May 1 NZST May 31 NZST
Twilights morning evening morning evening
Civil: start 6.39am, end 5.56pm start 7.05am, end 5.31pm
Nautical: start 6.07am, end 6.29pm start 6.31am, end 6.06pm
Astro: start 5.34am, end 7.01pm start 5.58am, end 6.39pm
May PHASES OF THE MOON, times NZ & UT
First quarter: May 1 at 8.38am (Apr 30, 20:38 UT)
Full Moon: May 7 at 10.45pm (10:45 UT)
Last quarter: May 15 at 2.03am (May 14, 14:03 UT)
New Moon: May 23 at 5.39am (May 22, 17:39 UT)
First quarter: May 30 at 3.30pm (03:30 UT)
PLANETS in MAY
MERCURY is at superior conjunction with the Sun on May 4. Following conjunction, it becomes an evening planet. By the end of May the planet sets some 80 minutes after the Sun. A little before 6pm, towards the end of May, it may be visible very low to the north-west.
VENUS, as an evening object, sets about 100 minutes after the Sun at the beginning of May. It will then be visible as a brilliant object rather low to the north-west soon after sunset. The elongation of Venus steadily decreases during May, especially after it is stationary on the 13th. By the 31st it will be only 5° from the Sun so unobservable.
Venus and Mercury are less than a degree apart on May 22. They will be very difficult to see, requiring a clear low horizon. Half an hour after sunset Venus will be only 2° up with Mercury to its upper left.
JUPITER and SATURN are about 5° apart throughout May. Saturn is stationary on the 11th, Jupiter on the 15th (NZ time). Hence both will be slow moving all month. The moon joins the two planets on the night of 12/13 May. It is about 3° from each planet about 1am.
PLUTO is 2° from Jupiter on the opposite side to Saturn.
MARS rises shortly after midnight. It moves to the east away from Jupiter and Saturn during May, crossing from Capricornus to Aquarius on the 8th. On May 16 the moon, near last quarter, will be 5° to the left of Mars an hour before sunrise.
URANUS moves up into the morning sky during May. It is too close to the Sun for observation early in the month, but by the end of May it will rise more than two and a half hours before the Sun. NEPTUNE, also a morning object, rises 4 hours before Uranus.
POSSIBLE BINOCULAR ASTEROIDS in MAY
May 1 NZST May 31 NZST
Mag Cons transit Mag Cons transit
(1) Ceres 9.2 Aqr .8.09am 9.0 Aqr 6.44am
(4) Vesta 8.5 Tau 2.43pm 8.4 Ori 1.39pm
CERES is a morning object. It rises at 1am on the 1st and 11.37pm on the 31st.
VESTA is an evening object getting low by the end of May. It sets at 7.30 pm NZST on the 1st and 6.18 pm on the 31st. Vesta is about 5° from Venus mid May and moves from Taurus to Orion on the 29th.
-- Brian Loader
6. Current Brightish Comets
Binocular Comet C/2020 F8 (SWAN)
This comet was seen by M. Mattiazzo on images from the Solar Wind Anisotropies (SWAN) camera on the Solar and Heliospheric
Observer (SOHO) spacecraft. Numerous ground-based observations followed.
A preliminary parabolic orbit by S. Nakano gives the comet's perihelion at 2020 May 27.5 TT at a distance of 0.4309 AU (65 million km) from the Sun. The comet is 0.555 AU (83 million km) from Earth on May 15. On current predictions the comet will be at its brightest at the end of May. Unfortunately it will be below NZ's northern horizon then.
Below are positions of C/2020 F8 (SWAN) at 6 a.m. NZST. m1 is the total magnitude, the magnitude of a star defocused to the comet's size. An m1 fainter than 3 is not easily seen by eye.
Apr. R.A.(2000)Dec. m1 May R.A.(2000)Dec. m1
h m ° ' h m ° '
21 23 20.0 -31 00 7.9 01 23 56.7 -17 44 6.3
22 23 22.9 -30 03 7.8 02 00 01.6 -15 46 6.1
23 23 26.0 -29 03 7.7 03 00 06.8 -13 37 6.0
24 23 29.1 -27 59 7.5 04 00 12.5 -11 17 5.8
25 23 33.0 -26 49 7.3 05 00 18.5 -08 47 5.6
26 23 36.0 -25 35 7.2 06 00 25.0 -06 04 5.4
27 23 39.7 -24 15 7.0 07 00 31.9 -03 09 5.2
28 23 43.5 -22 48 6.8 08 00 39.4 -00 03 5.1
29 23 47.7 -21 15 6.7 09 00 47.4 +03 15 4.9
30 23 52.0 -19 34 6.5 10 00 56.0 +06 42 4.7
11 01 05.3 +10 17 4.6
12 01 15.2 +13 57 4.4
13 01 25.7 +17 39 4.3
14 01 37.0 +21 17 4.2
15 01 48.8 +24 50 4.1
16 02 01.3 +28 12 4.0
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Comet Atlas (C/2019 Y4)
There has been much northern hemisphere interest in this comet as it appeared that it might be bright at perihelion at the end of May. It would have been below NZ's north horizon then, as it is now.
The comet faded in March and images obtained in April show that it is breaking up. The nucleus, the solid part, has fragmented into at least four pieces. This isn't too surprising as C/2019 Y4 is itself a fragment of a larger comet. It is in the same orbit as the Great Comet C/1844 Y1. Both comets have an orbital period of around 4000 years so C/2019 Y4 can't be a reappearance of C/1844 Y1. It'll be interesting to see if C/2019 Y4
even gets to perihelion before it fragments completely.
7. 'Eye on the Sky' Video
John Drummond has produced his first 'Eye on the NZ Sky' video on Venus as part of the RASNZ initiative to promote astronomy through the Lockdown. John has kept it under 10-minutes length and has made it beginner/child and naked eye friendly.
There were many teething issues and challenges in producing this initial videos. There will be other regular videos in this series and the quality will be much better.
Here's the link -
https://www.youtube.com/watch?v=fZxVhDxxIqE
-- Nalayini Brito
8. New Zealand Astrophotography Competition - Closes September 21
Entries are sought for the 2020 New Zealand Astrophotography competition.
The competition is fully endorsed by the Royal Astronomical Society of New Zealand and is the nation's largest astrophotography competition.
See last month's Newsletter for details.
The competition cut-off date is the 21st of September and the competition awards will be announced at the annual Burbidge dinner which is the Auckland Astronomical Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.
You can find the rules and entry forms on the AAS website at https://www.astronomy.org.nz/new/public/default.aspx
-- From Jonathan Green's posting nnzastronomers Yahoo group
9. Stargazers Getaway September 18-20
Stargazers Getaway 2020 at Camp Iona on Friday September 18th to Sunday 20th. This is New Moon, so we are targeting this weekend for dark skies! Camp Iona is near Herbert, south of Oamaru.
See last month's Newsletter for details and
https://www.facebook.com/events/943327669369996/
10. 14th Asia-Pacific Regional IAU Meeting Cancelled
The 14th Asia-Pacific Regional IAU Meeting that was to be held in Perth, Western Australia, on July 6 - 10, 2020 has been cancelled due to the covid-19 pandemic. See statement on meeting's website at
www.aprim2020.org .
11. Communicating Astronomy with the Public Conference
From 21 to 25 September 2020, Macquarie University in Sydney, Australia, and the International Astronomical Union (IAU) Commission C2 - Communicating Astronomy with the Public (CAP), will host the world's largest conference on astronomy communication: Communicating Astronomy with the Public 2020 (CAP2020). Professionals from science communication, informal education, planetaria and science centres, as well as professional and amateur astronomers, journalists and creatives, are invited to attend the conference to exchange ideas and discuss best practice.
See last month's Newsletter for details, also
https://www.communicatingastronomy.org/cap2020/
The website now says "Abstract & grant applications deadline extended until 30 April 2020." It also notes that the CAP 2020 organisers are closely monitoring the Covid-19 outbreak.
12. Fossil Shells Tell Cretaceous Day Length
It has long been known that the Earth's rotation is slowing down. Growth rings on fossil shells show that that the number of days in a lunar month, via tide cycles, and the number of days in a year have become less as the day lengthens.
New results from fossil mollusc shells from the late Cretaceous have added much more detail. The new study analysed a single individual that lived for over nine years in a shallow seabed in the tropics — a location which is now, 70-million-years later, dry land in the mountains of Oman.
The new method focused a laser on small bits of shell, making holes 10 microns in diameter, or about as wide as a red blood cell. Trace elements in these tiny samples reveal information about the temperature and chemistry of the water at the time the shell formed. The analysis provided accurate measurements of the width and number of daily growth rings as well as seasonal patterns. The researchers used seasonal variations in the fossilized shell to identify years. The study was led by Niels de Winter, an analytical geochemist at Vrije Universiteit Brussel.
The new study found the composition of the shell changed more over the course of a day than over seasons, or with the cycles of ocean tides. The fine-scale resolution of the daily layers shows the shell grew much faster during the day than at night.
This result suggests daylight was more important to the lifestyle of the ancient mollusc than might be expected if it fed itself primarily by filtering food from the water, like modern day clams and oysters, according to the authors. De Winter said the molluscs likely had a relationship with an indwelling symbiotic species that fed on sunlight, similar to living giant clams, which harbour symbiotic algae.
De Winter’s careful count of the number of daily layers found 372 for each yearly interval. This was not a surprise, because scientists know days were shorter in the past. The result is, however, the most accurate now available for the late Cretaceous, and has a surprising application to modelling the evolution of the Earth-Moon system.
The length of a year has been constant over Earth’s history, because Earth’s orbit around the Sun does not change. But the number of days within a year has been shortening over time because days have been growing longer. The length of a day has been growing steadily longer as friction from ocean tides, caused by the Moon’s gravity, slows Earth’s rotation.
The pull of the tides accelerates the Moon a little in its orbit, so as Earth’s spin slows, the Moon moves farther away. The moon is pulling away from Earth at 3.82 cm per year. Precise laser measurements of distance to the Moon from Earth have demonstrated this increasing distance since the Apollo program left helpful reflectors on the Moon’s surface.
The Moon’s rate of retreat has changed over time, and information from the past, like a year in the life of an ancient clam, helps researchers reconstruct that history and model of the formation of the moon. Because in the history of the Moon, 70 million years is a blink in time, de Winter and his colleagues hope to apply their new method to older fossils and catch snapshots of days even deeper in time.
-- From an American Geological Union AGU (www.agu.org) press release forwarded by Karen Pollard. The lengthy press release is no longer available on-line but the Newsletter editor is happy to forward it on request. The original paper can be seen at
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019PA003723
13. Katherine Johnson Obituary
As she ran her eyes over the flight-test calculation sheets the engineer had given her, Katherine Goble (as she then was) could see there was something wrong with them. The engineer had made an error with a square root. And it was going to be tricky to tell him so. It was her first day on this assignment, when she and another girl had been picked out of the computing pool at the Langley aeronautical laboratory, later part of NASA, to help the all-male Flight Research Unit. But there were other, more significant snags than simply being new.
Most obviously, he was a man and she was a woman. In 1953 women did not question men. They stayed in their place, in this case usually the computing pool, tapping away on their Monroe desktop calculators or filling sheets with figures, she as neatly turned out as all the rest. Men were the grand designers, the engineers; the women were “computers in skirts”, who were handed a set of equations and exhaustively, diligently checked them. Men were not interested in things as small as that.
And, most difficult of all, she was Coloured, and he was White. The lab might be recruiting black mathematicians, but the door was not fully open; her pool was called “Coloured Computing”, and was segregated. As she sat down with the new team that morning, the men next to her had moved away. She was not sure why, but the world was like that, and she refused to be bothered by it. Since the café was segregated, she ate at her desk. There was no Coloured restroom, so she used the White one. A few years back, when the bus taking her to her first teaching job in Marion, Virginia, had crossed the state line from West Virginia, all the blacks had been told to get off and take taxis. She refused until she was asked nicely. But it could be unwise to push a white man too far.
Nonetheless, this engineer’s calculation was wrong. If she did not ask the question, an aircraft might not fly, or might fly and crash. So, very carefully, she asked it. Was it possible that he could have made a mistake? He did not admit it but, by turning the colour of a cough drop, he ceded the point.
She asked more such questions, and they got her noticed. As the weeks passed, the men “forgot” to return her to the pool. Her incessant “Why?” and “How?” made their work sharper. It also challenged them. Why were their calculations of aerodynamic forces so often out? Because they were maths graduates who had forgotten their geometry, whereas she had not; her high-school brilliance at maths had led to special classes on analytic geometry in which she, at 13, had been the only pupil. Why was she not allowed to get her name on a flight-trajectory report when she had done most of the work, filling her data sheets with figures for days? Because women didn’t. That was no answer, so she got her name on the report, the first woman to be so credited. Why was she not allowed into the engineers’ lectures on orbital mechanics and rocket propulsion? Because “the girls don’t go”. Why? Did she not read Aviation Week, like them? She soon became the first woman there.
As NASA’s focus turned from supersonic flight to flights in space, she was therefore deeply involved, though still behind the scenes. This excited her, because if her first love was mathematics — counting everything as a child, from plates to silverware to the number of steps to the church — her second was astronomy, and the uncountable stars. A celestial globe now joined the calculator on her desk. She had to plot the trajectories of spacecraft, developing the launch window and making sure — as soon as humans took off — that the module could get back safely. This involved dozens of equations to calculate, at each moment, which bit of Earth the spacecraft was passing over, making allowances for the tilt of the craft and the rotation of the planet. She ensured that Alan Shepard’s Mercury capsule splashed down where it could be found quickly in 1961, and that John Glenn in 1962 could return safely from his first orbits of the Earth. Indeed, until “the girl”, as he called her (she was 43), had checked the figures by hand against those of the newfangled electronic computer, he refused to go.
That checking took her a day and a half. Later she calculated the timings for the first Moon landing (with the astronauts’ return), and worked on the Space Shuttle. She also devised a method by which astronauts, with one star observation checked against a star chart, could tell where they were. But in the galaxy of space-programme heroes, despite her 33 years in the Flight Research Unit, for a long time she featured nowhere.
It did not trouble her. First, she also had other things to do: raise her three daughters, cook, sew their clothes, care for her sick first husband. Second, she knew in her own mind how good she was — as good as anybody. She could hardly be unaware of it, when she had graduated from high school at 14 and college at 18, expert at all the maths anyone knew how to teach her. But she typically credited the help of other people, especially her father, the smartest man she knew, a farmer and a logger, who could look at any tree and tell how many board-feet he could get out of it; and who had sold the farm and moved the family so that she and her siblings could all get a fine schooling and go to college. And last, at NASA, she had not worked alone. She had been one of around a dozen black women mathematicians who were equally unknown. But when their story emerged in the 21st century, most notably in a book and a film called “Hidden Figures”, she had a NASA building named after her, a shower of honorary doctorates and — the greatest thrill — a kiss from Barack Obama as he presented her, at 96, with the Presidential Medal of Freedom.
This attention was all the more surprising because, for her, the work had been its own reward. She just did her job, enjoying every minute. The struggles of being both black and a woman were shrugged away. Do your best, she always said. Love what you do. Be constantly curious. And learn that it is not dumb to ask a question; it is dumb not to ask it. Not least, because it might lead to the small but significant victory of making a self-proclaimed superior realise he can make a mistake.
Katherine Johnson died on February 24th aged 101.
-- This article appeared in the Obituary section of the print edition of The Economist February 27th 2020, page 74, under the headline "The girl who asked questions"
14. Neutron Star Size from Gravitational Waves
Scientists have combined observations of gravitational waves from a neutron star collision with nuclear theory to shed light on the size and nature of neutron stars.
Neutron stars, the collapsed cores of massive stars, compress matter so tightly that atoms break apart and nearly everything converts into neutrons. As a result, about 1½ Suns’ worth of mass squeezes into these Manhattan-size objects. Most of this matter, perhaps all of it, is in the form of neutrons, but some theories suggest that deep within neutron stars, neutrons themselves dissociate, leaving a soup of quarks and gluons.
There’s no way to peer inside a neutron star, of course. But their size betrays their interior — the smaller a neutron star, the more it compresses its innards. So by taking a ruler to neutron stars, scientists can probe their nature.
In a study appearing March 9th in Nature Astronomy, Collin Capano (Max Planck Institute for Gravitational Physics and Leibniz University Hannover, Germany) and colleagues examine the ripples in spacetime released in a neutron star merger. Combining these gravitational-wave observations with nuclear theory, the scientists estimate that a typical neutron star would span about 22 km.
This is the most precise measurement obtained from gravitational waves, and it has important implications for future observations.
The Laser Interferometer Gravitational-wave Observatory (LIGO) detectors witnessed spacetime ripples coming from two colliding neutron stars on August 17, 2017. The event, known as GW170817, marked the first time that astronomers could see both light and gravitational waves coming from the same source.
While the gravitational-wave signal showed the neutron stars spiralling inward and merging into a single object, light released across the electromagnetic spectrum showed the aftereffect — an explosion known as a kilonova that was visible from 130 million light-years away. At the centre of the explosion, observations suggest a short-lived “hypermassive” neutron star formed that then collapsed into a black hole.
To understand the nature of the neutron stars that collided, Capano and colleagues wielded mathematics describing the nature of neutron star material, known as an equation of state. After folding in the gravitational-wave and electromagnetic observations, the equation yields the size of a typical neutron star: between 20.8 and 23.8 km across. This estimate is twice as precise as previous results.
“Like we've seen in other results from analysing GW170817, gravitational-wave astronomy has begun to meaningfully constrain the range of possibilities for neutron star matter,” says Jocelyn Read (California State University, Fullerton). “It suggests neutron stars are on the compact side.”
More compact neutron stars might mean more exotic interiors. But Read cautions that it’s not quite that simple. Even larger sizes could accommodate quark-soup cores, while smaller sizes could still be “boring” mostly-neutron objects.
Capano agrees. “We just don’t have enough data at the moment to say conclusively what happens in the core,” he says.
More gravitational-wave events will help, Capano adds, as will ongoing observations from the Neutron Star Interior Composition Explorer (NICER) instrument aboard the International Space Station. Upcoming physics experiments will also play a role in better nailing down the nuclear theory.
Meanwhile, the compact nature of neutron stars has immediate implications for gravitational-wave observations of encounters between neutron stars and black holes. A smaller, more tightly packed neutron star would be more difficult for a black hole to tear apart before pulling it in, so black holes are more likely to swallow neutron stars whole.
That means that if a black hole and a neutron star collide, we wouldn’t expect any light-emitting counterpart — astronomers would have to rely on gravitational-wave signals alone. Only if the black hole were exceedingly small or spinning rapidly would any light be produced, Capano explains.
Nevertheless, advances in our understanding of neutron stars are on the horizon. The LIGO Collaboration, as well as the Virgo Collaboration in Italy, are analysing results from gravitational-wave signals detected since April 2019. Their list of bona fide events, expected at the end of April 2020, should include multiple black hole mergers and at least one neutron star collision.
-- Monica Young's article on https://skyandtelescope.org/astronomy-news/gravitational-waves-put-ruler-to-neutron-stars/
15. Mid-Size Black Hole Found?
New data from the NASA/ESA Hubble Space Telescope have provided the strongest evidence yet for mid-sized black holes in the Universe. Hubble confirms that this “intermediate-mass” black hole dwells inside a dense star cluster.
Intermediate-mass black holes (IMBHs) are a long-sought “missing link” in black hole evolution. There have been a few other IMBH candidates found to date. They are smaller than the supermassive black holes that lie at the cores of large galaxies, but larger than stellar-mass black holes formed by the collapse of massive stars. This new black hole is over 50 000 times the mass of our Sun.
IMBHs are hard to find. “Intermediate-mass black holes are very elusive objects, and so it is critical to carefully consider and rule out alternative explanations for each candidate. That is what Hubble has allowed us to do for our candidate,” said Dacheng Lin of the University of New Hampshire, principal investigator of the study.
Lin and his team used Hubble to follow up on leads from NASA’s Chandra X-ray Observatory and the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton), which carries three high-throughput X-ray telescopes and an optical monitor to make long uninterrupted exposures providing highly sensitive observations.
“Adding further X-ray observations allowed us to understand the total energy output,” said team member Natalie Webb of the Université de Toulouse in France. “This helps us to understand the type of star that was disrupted by the black hole.”
In 2006 these high-energy satellites detected a powerful flare of X-rays, but it was not clear if they originated from inside or outside of our galaxy. Researchers attributed it to a star being torn apart after coming too close to a gravitationally powerful compact object, like a black hole.
Surprisingly, the X-ray source, named 3XMM J215022.4?055108, was not located in the centre of a galaxy, where massive black holes normally reside. This raised hopes that an IMBH was the culprit, but first another possible source of the X-ray flare had to be ruled out: a neutron star in our own Milky Way galaxy, cooling off after being heated to a very high temperature. Neutron stars are the extremely dense remnants of an exploded star.
Hubble was pointed at the X-ray source to resolve its precise location. Deep, high-resolution imaging confirmed that the X-rays emanated not from an isolated source in our galaxy, but instead in a distant, dense star cluster on the outskirts of another galaxy — just the sort of place astronomers expected to find evidence for an IMBH. Previous Hubble research has shown that the more massive the galaxy, the more massive its black hole. Therefore, this new result suggests that the star cluster that is home to 3XMM J215022.4?055108 may be the stripped-down core of a lower-mass dwarf galaxy that has been gravitationally and tidally disrupted by its close interactions with its current larger galaxy host.
IMBHs have been particularly difficult to find because they are smaller and less active than supermassive black holes. They do not have readily available sources of fuel, nor do they have a gravitational pull that is strong enough for them to be constantly drawing in stars and other cosmic material and producing the tell-tale X-ray glow. Astronomers therefore have to catch an IMBH red-handed in the relatively rare act of gobbling up a star. Lin and his colleagues combed through the XMM-Newton data archive, searching hundreds of thousands of sources to find strong evidence for this one IMBH candidate. Once found, the X-ray glow from the shredded star allowed astronomers to estimate the black hole’s mass.
Confirming one IMBH opens the door to the possibility that many more lurk undetected in the dark, waiting to be given away by a star passing too close. Lin plans to continue this meticulous detective work, using the methods his team has proved successful.
“Studying the origin and evolution of the intermediate mass black holes will finally give an answer as to how the supermassive black holes that we find in the centres of massive galaxies came to exist,” added Webb.
Black holes are one of the most extreme environments humans are aware of, and so they are a testing ground for the laws of physics and our understanding of how the Universe works. Does a supermassive black hole grow from an IMBH? How do IMBHs themselves form? Are dense star clusters their favoured home? With a confident conclusion to one mystery, Lin and other black hole astronomers find they have many more exciting questions to pursue.
-- From the Hubble Space Telescope press release forwarded by Karen Pollard. See the original at https://www.spacetelescope.org/news/heic2005/
16. 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 2020 year starts at $40 for an ordinary
member, which includes an electronic subscription to our journal
'Southern Stars'.
17. Quotes
"Dwell on the beauty of life. Watch the stars, and see yourself running with them." Marcus Aurelius, Roman Emperor and Stoic philosopher (121-180). From The Otago Daily Times.
"Just as we are asking our frail, vulnerable, easily confused old people to stay indoors, America is being asked to put them in the White House." -- UK Times writer Matt Chorley quoted in The Listener.
"Please note: The post-apocalyptical fiction section has been moved to Current Affairs." -- Book shop notice posted on Facebook.
"Here's a very appropriate analogy: 'The curve is flattening; we can start lifting restrictions now' = 'The parachute has slowed our rate of descent; we can take it off now.'" -- Seen on Facebook.
Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
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You can view updated paths and other details at:
http://www.occultations.org.nz/
Minor Planet Occultation Updates:
================================
This email describes updates for minor planet occultations for April 2020.
If you do not wish to receive these updates please advise
the Occultation Section.
You can view updated paths and other details at:
http://www.occultations.org.nz/
Minor Planet Occultation Updates:
================================
Events of particular ease or importance below are marked: *****
***** Apr 1 (1841) MASARYK: Star Mag 10.1, Max dur 2.2 sec, Mag Drop 7.2
Somewhat uncertain path across the North Island of New Zealand, passing near Auckland and over Whakatane.
Details: http://occultations.org.nz/planet/2020/updates/200401_1841_67140_u.htm
Apr 2 (85) IO: Star Mag 11.9, Max dur 14.6 sec, Mag Drop 0.9
Path across West Australia, passing over Geraldton.
Details: http://occultations.org.nz/planet/2020/updates/200402_85_64596_u.htm
Apr 3 (347) PARIANA: Star Mag 11.1, Max dur 4.4 sec, Mag Drop 2.7
West Australia, Northern Territory, Queensland and New South Wales, passing over Alice Springs, Birdsville, Coonabarrabran and Newcastle.
Details: http://occultations.org.nz/planet/2020/updates/200403_347_64602_u.htm
Apr 4 2015KP173: No update for this TNO event
Apr 4 (546) HERODIAS: Star Mag 11.4, Max dur 6.2 sec, Mag Drop 3.3
Northern West Australia, Northern Territory and South Australia, passing over Port Augusta, Adelaide and Mount Gambier.
Details: http://occultations.org.nz/planet/2020/updates/200404_546_64622_u.htm
Apr 5 (85) IO: Star Mag 12.3, Max dur 15.8 sec, Mag Drop 0.7
Central-western West Australia, passing over Geraldton, during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200405_85_64632_u.htm
Apr 6 (559) NANON: Star Mag 11.9, Max dur 2.6 sec, Mag Drop 3.3
South Northern Territory and southern Queensland and north-eastern New South Wales, passing over Byron Bay.
Details: http://occultations.org.nz/planet/2020/updates/200406_559_68086_u.htm
***** Apr 7 (1690) MAYRHOFER: Star Mag 10.4, Max dur 3.5 sec, Mag Drop 5.9
Somewhat uncertain path across Queensland, Northern Territory and New Zealand, passing near Caloundra and Taupo.
Details: http://occultations.org.nz/planet/2020/updates/200407_1690_67142_u.htm
Apr 7 (1194) ALETTA: Star Mag 11.0, Max dur 7.0 sec, Mag Drop 3.3
Slightly uncertain path across south-eastern New South Wales, central Victoria, southern South Australia and south-western West Australia, passing over Kilmore, Kingston SE and Waroona.
Details: http://occultations.org.nz/planet/2020/updates/200407_1194_64644_u.htm
Apr 8 (454) MATHESIS: Star Mag 12.0, Max dur 4.2 sec, Mag Drop 2.3
West Australia, Northern Territory and Queensland, during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200408_454_64656_u.htm
***** Apr 10 (66) MAJA: Star Mag 11.3, Max dur 20.7 sec, Mag Drop 2.8
Path across New Zealand, passing over Auckland and Coromandel.
Details: http://occultations.org.nz/planet/2020/updates/200410_66_64666_u.htm
Apr 10 (480) HANSA: Star Mag 10.4, Max dur 2.8 sec, Mag Drop 1.0
Central West Australia, Northern Territory, northern South Australia and Queensland, passing Kalbarri, Birdsville and Maryborough.
Details: http://occultations.org.nz/planet/2020/updates/200410_480_67144_u.htm
Apr 11 (92) UNDINA: Star Mag 12.1, Max dur 10.1 sec, Mag Drop 0.6
New Zealand, northern Victoria, South Australia and West Australia, passing over Dunedin, Alexandra, Orbost, Benalla, Echuca and Whyalla.
Details: http://occultations.org.nz/planet/2020/updates/200411_92_64674_u.htm
Apr 11 (159) AEMILIA: Star Mag 11.3, Max dur 11.4 sec, Mag Drop 1.8
Queensland, Northern Territory and West Australia, passing over Ingham, Townsville, Cardwell and Wyndham.
Details: http://occultations.org.nz/planet/2020/updates/200411_159_64676_u.htm
***** Apr 12 (6392) TAKASHIMIZUNO: Star Mag 8.7, Max dur 0.7 sec, Mag Drop 8.5
Significantly uncertain path across West Australia, southern South Australia, northern Victoria, southern New South Wales and New Zealand, passing over Ceduna, Swan Hill, Eden and near Wellington during late morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200412_6392_68096_u.htm
Apr 13 (626) NOTBURGA: Marginal event during late morning twilight mostly over Tasman Sea.
***** Apr 14 (1691) OORT: Star Mag 8.8, Max dur 1.2 sec, Mag Drop 7.8
Somewhat uncertain path across West Australia, South Australia and New South Wales, passing over Carnarvon, Wagga Wagga, Narooma and Bermagui.
Details: http://occultations.org.nz/planet/2020/updates/200414_1691_67150_u.htm
Apr 14 (312) PIERRETTA: Star Mag 12.3, Max dur 8.9 sec, Mag Drop 0.9
Somewhat uncertain path across central Queensland, north-western New South Wales and central South Australia, passing near Sarina, Mackay, Port Pirie and Maitland.
Details: http://occultations.org.nz/planet/2020/updates/200414_312_64696_u.htm
Apr 15 (954) LI: Star Mag 12.5, Max dur 4.6 sec, Mag Drop 2.1
Slightly uncertain path across New Zealand, New South Wales, northern South Australia and central West Australia, passing over Wanganui, Sydney, Bathurst, Parkes and Karratha.
Details: http://occultations.org.nz/planet/2020/updates/200415_954_64706_u.htm
***** Apr 15 (1288) SANTA: Star Mag 9.2, Max dur 3.2 sec, Mag Drop 6.8
Somewhat uncertain path across South Island of New Zealand and southern Tasmania, passing over Christchurch and Hobart.
Details: http://occultations.org.nz/planet/2020/updates/200415_1288_67152_u.htm
Apr 15 (1116) CATRIONA: Star Mag 11.0, Max dur 4.7 sec, Mag Drop 4.7
Somewhat uncertain path across western Queensland and eastern South Australia, running from Weipa to Murray Bridge.
Details: http://occultations.org.nz/planet/2020/updates/200415_1116_64708_u.htm
Apr 17 2003HF57: No update for this unnumbered Centaur event.
Apr 17 (1771) MAKOVER: Star Mag 12.1, Max dur 14.5 sec, Mag Drop 4.0
Somewhat uncertain path across northern Queensland and New Zealand, passing over Cape Melville and Wellington.
Details: http://occultations.org.nz/planet/2020/updates/200417_1771_64726_u.htm
Apr 18 (69) HESPERIA: Star Mag 11.7, Max dur 5.5 sec, Mag Drop 0.9
Path across south-eastern Queensland, during evening twilight.
Details: http://occultations.org.nz/planet/2020/updates/200418_69_64730_u.htm
Apr 18 (105) ARTEMIS: Star Mag 11.9, Max dur 5.2 sec, Mag Drop 2.0
South Australia, north-western Victoria and central New South Wales, passing over Adelaide, Murray Bridge, Mildura, Parkes and Taree.
Details: http://occultations.org.nz/planet/2020/updates/200418_105_64732_u.htm
***** Apr 18 (389) INDUSTRIA: Star Mag 10.6, Max dur 3.4 sec, Mag Drop 2.5
West Australia, northern South Australia and central New South Wales, passing over Onslow, Broken Hill, Goulburn and Ulladulla.
Details: http://occultations.org.nz/planet/2020/updates/200418_389_64734_u.htm
Apr 19 (1282) UTOPIA: Star Mag 12.5, Max dur 5.2 sec, Mag Drop 3.1
Somewhat uncertain path across Queensland, northern South Australia and southern West Australia, passing near Rockhampton, Kalgoorlie and Perth.
Details: http://occultations.org.nz/planet/2020/updates/200419_1282_64740_u.htm
Apr 19 (1145) ROBELMONTE: Star Mag 11.0, Max dur 2.7 sec, Mag Drop 3.1
Somewhat uncertain path across Queensland, Northern Territory and northern West Australia, running from Marlborough to Karratha.
Details: http://occultations.org.nz/planet/2020/updates/200419_1145_68104_u.htm
Apr 19 (1977) SHURA: Star Mag 11.7, Max dur 18.0 sec, Mag Drop 4.1
Large uncertainty path across eastern West Australia.
Details: http://occultations.org.nz/planet/2020/updates/200419_1977_64744_u.htm
Apr 21 (554) PERAGA: Star Mag 11.0, Max dur 6.9 sec, Mag Drop 3.1
Central West Australia, northern South Australia and southern Queensland, running from Shark Bay to Caboolture.
Details: http://occultations.org.nz/planet/2020/updates/200421_554_64756_u.htm
***** Apr 22 (1159) GRANADA: Star Mag 8.3, Max dur 3.3 sec, Mag Drop 6.6
Somewhat uncertain path across southern New South Wales, north-western Victoria, southern South Australia and south-western West Australia, passing over Wollongong, Swan Hill, Kangaroo Island and Albany.
Details: http://occultations.org.nz/planet/2020/updates/200422_1159_67026_u.htm
Apr 22 (670) OTTEGEBE: Star Mag 8.0, Max dur 9.3 sec, Mag Drop 6.4
Slightly uncertain path across eastern West Australia, running from Point Culver to Broome.
Details: http://occultations.org.nz/planet/2020/updates/200422_670_67028_u.htm
***** Apr 23 (99) DIKE: Star Mag 12.3, Max dur 7.1 sec, Mag Drop 1.1
Eastern areas of New Zealand's North and South Islands, passing over Gisborne, Wellington, Christchurch and Dunedin.
Details: http://occultations.org.nz/planet/2020/updates/200423_99_64768_u.htm
Apr 23 (165) LORELEY: Star Mag 11.9, Max dur 6.2 sec, Mag Drop 1.7
South Australia, then across north-western Victoria and New South Wales, passing over Adelaide, Mildura and Dubbo during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200423_165_64770_u.htm
Apr 24 (389) INDUSTRIA: Star Mag 12.3, Max dur 3.1 sec, Mag Drop 1.2
Path across New South Wales during evening twilight then across New Zealand, passing over Westport.
Details: http://occultations.org.nz/planet/2020/updates/200424_389_64776_u.htm
***** Apr 24 (779) NINA: Star Mag 8.9, Max dur 21.5 sec, Mag Drop 3.5
Southern New South Wales, north-western Victoria, South Australia and southern West Australia, passing over Nowra, Wagga Wagga, Maitland and Jurien.
Details: http://occultations.org.nz/planet/2020/updates/200424_779_64778_u.htm
Apr 25 (322) PHAEO: Marginal event that will cross NZ south island shortly before sunrise.
Apr 25 (546) HERODIAS: Star Mag 11.6, Max dur 8.8 sec, Mag Drop 2.8
Slightly uncertain path across eastern Northern Territory and western South Australia, passing over Tennant Creek and Alice Springs.
Details: http://occultations.org.nz/planet/2020/updates/200425_546_64788_u.htm
Apr 25 (471325) 2011KT19: No update for this TNO event over western Australia.
Apr 26 (186) CELUTA: Star Mag 11.8, Max dur 6.7 sec, Mag Drop 1.1
Somewhat uncertain path across Queensland, western New South Wales, extreme north-western Victoria and south-eastern South Australia, running from Bowen to Kingston SE.
Details: http://occultations.org.nz/planet/2020/updates/200426_186_64796_u.htm
Apr 28 (120) LACHESIS: Star Mag 9.8, Max dur 12.1 sec, Mag Drop 3.6
path across Northern Territory and Queensland, passing over Cloncurry and Mount Isa.
Details: http://occultations.org.nz/planet/2020/updates/200428_120_64804_u.htm
Note: for some events there will be an additional last minute update so check
for one, if you can, on the day of the event or in the days leading up to it.
You may need to click "Reload" or "Refresh" in your browser to see the updated page.
Please report all attempts at observation to the address below.
(PLEASE report observations on a copy of the report available from our website).
Peter Litwiniuk
---------------------------------------------
RASNZ Occultation Section
P.O.Box 3181 / Wellington, 6140 / New Zealand
---------------------------------------------
WEBSITE: http://www.occultations.org.nz/
Email: Director@occultations.org.nz
---------------------------------------------
---------------------------------------------
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Please note:
My standard caveat that these are the views of a learned amateur, not a professional in the sector, applies as always.
The above post/email/update represents my own words, views, research and opinions, unless stated otherwise the above work
represents my own writing. I’ll give credit or thanks if I have used or represented other people’s words and/or opinions.
The links and references listed below represent the work and research of the respective author’s.
Questions and constructive criticism are always welcome, however I don’t believe anything written here by myself is any reason for impolite behaviour.
Thanks for your time and I hope you have enjoyed reading.
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This months research Papers 20_04_2020
RASNZ_20_04_2020
Further links and discussion can be found at the groups/links below
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https://www.facebook.com/groups/5889909863/
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Blogger Posts
http://laintal.blogspot.com/
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Research papers
An interstellar origin for high-inclination Centaurs
https://arxiv.org/abs/2004.10510
The multi-planet system TOI-421 A warm Neptune
https://arxiv.org/abs/2004.10095
Searching for the near infrared counterpart of Proxima c
https://arxiv.org/abs/2004.06685
Strong Near-Infrared Spectral Variability of the Young Cloudy L Dwarf Companion VHS J1256-1257 b
https://arxiv.org/abs/2004.05170
Habitability is a continuous property of nature
https://arxiv.org/abs/2004.06470
The Astrobiological Copernican Weak and Strong Limits for Extraterrestrial Intelligent Life
https://arxiv.org/abs/2004.03968
Radar evidence of subglacial liquid water on Mars
https://arxiv.org/abs/2004.04587
Detectability of Life Using Oxygen on Pelagic Planets and Water Worlds
https://arxiv.org/abs/2004.03631
Global Mapping of the Surface Composition on an Exo-Earth using Color Variability
https://arxiv.org/abs/2004.03931
an astrometric calibration field for high-contrast imagers in Baade's Window
https://arxiv.org/abs/2004.02923
Atmospheric convection plays a key role in the climate of tidally-locked terrestrial exoplanets
https://arxiv.org/abs/2004.03007
The effect of high nitrogen pressures on the habitable zone and an appraisal of greenhouse states
https://arxiv.org/abs/2004.00229
Outstanding Challenges of Exoplanet Atmospheric Retrievals
https://arxiv.org/abs/2003.14311
Focal Plane Wavefront Sensing with the FAST TGV Coronagraph
https://arxiv.org/abs/2003.13692
Salty Oceans in Low Mass Habitable Planets and Global Climate Evolution
https://arxiv.org/abs/2003.13107
Stellar Driven Evolution of Hydrogen-Dominated Atmospheres
https://arxiv.org/abs/2003.13412
A kinematically hot population of young stars in the solar neighbourhood
https://arxiv.org/abs/2003.13369
The Habitability of Large Elliptical Galaxies
https://arxiv.org/abs/2003.13643
Uranian Satellite Formation by Evolution of a Water Vapor Disk
https://arxiv.org/abs/2003.13582
From Super-Earths to Mini-Neptunes
https://arxiv.org/abs/2003.13348
Earth-size planet formation in the habitable zone of circumbinary stars
https://arxiv.org/abs/2003.11682
Habitability of polar regions in tidally locked extrasolar planet near the M-Dwarf stars
https://arxiv.org/abs/2003.11732
Explaining the Cold Temperatures Retrieved from Transmission Spectra of Exoplanet Atmospheres
https://arxiv.org/abs/2003.11548
Atmospheric evolution from noble gas and Nitrogen on Earth Mars & Venus
https://arxiv.org/abs/2003.11431
An information theoretic framework for classifying exoplanetary system architectures
https://arxiv.org/abs/2003.11098
Delivery of water and volatiles to the terrestrial planets and the Moon
https://arxiv.org/abs/2003.09982
Human wealth evolution trends and fluctuations
https://arxiv.org/abs/2003.11502
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Interesting News items
Earth-Size, Habitable Zone Planet Found Hidden in Early NASA Kepler Data
http://astrobiology.com/2020/04/earth-size-habitable-zone-planet-found-hidden-in-early-nasa-kepler-data.html
Earth-Size, Habitable-Zone Planet Found Hidden in Early NASA Kepler Data
https://www.jpl.nasa.gov/news/news.php?feature=7639
Interesting Earth-sized Planet Turns Up in Kepler Data
https://www.centauri-dreams.org/2020/04/16/kepler-1649c-interesting-earth-sized-planet-turns-up-in-kepler-data/
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Updates from Andrew B,
Mars Science Laboratory Curiosity.
Sols 2,723 & 2,724. Saturday 4th & Sunday 5th April 2020.
LMST = Local Mars Standard Time in Gale Crater.
Sol 2,723. The larger and inner Mars moon Phobos passed in front of the Sun as seen from MSL Curiosity, using the 100 mm MastCam, Mast Camera. Phobos was passing from bottom to top.
The Sun & Phobos appeared in front of the constellation of Taurus the Bull, between the horns, between the stars Al Nath / Beta Tauri and Tianguan / Zeta Tauri. Just north of M1, The Crab Nebula.
Mars was 220.5 million KM / 137.1 million miles from the Sun and Phobos was only 6,844 KM / 4,253 miles away from MSL Curiosity during this observation.
Phobos is only 27 KM by 22 KM by 18 KM / 17 by 14 by 11 miles in size, orbits Mars at a mean distance of 9,376 KM / 5,822 miles once every 7 hours and 22 minutes. Phobos appears to have a density of 1.88 g/cm3, so likely to be a rubble pile held together by gravity.
Phobos experiences a wide range of surface temperatures from a maximum of minus 4 Celsius / 25 Fahrenheit or 269 Kelvin to a minimum of minus 112 Celsius / minus 170 Fahrenheit or 161 Kelvin.
Phobos orbits Mars once every 7 hours and 22 minutes, where as Mars rotates on it's axis once every 24 hours and 37 minutes (very similar to Earth's 23 hours and 56 minutes), meaning that Phobos is lapping the rotation of Mars. Therefore to an observer on the surface, Phobos rises in the west and sets in the east. The Sun and other astronomical objects on Mars rise in the east and set in the west as on Earth. Phobos crosses the sky from west to east in 4 hours & 14 minutes then sets for 11 hours & six minutes.
Sol 2,724. A stunning Navigation Camera shot showing the Earth in the evening Martian twilight as the Martian evening star. The Earth appeared in front of the constellation of Cancer the Crab, the Earth very bright at magnitude minus 1.88. The Earth was 214.2 million KM / 133.1 million miles away. I have made an annotated version.
In theory the planet Venus and the stars Castor / Alpha Geminorum and Pollux / Beta Geminorum should be visible. Perhaps a professionally tidied up version will show all of these.
MSL Curisosty has climbed 465 metres / 1,526 feet since landing from a point 18 metres / 59 feet below the mean level of the Gale Crater floor, so is 483 metres / 1,585 feet above the mean floor of Gale Crater. Has also driven 24.051 KM / 14.944 miles since landing.
MSL Curiosity was climbing the 5,500 metre / 18,050 foot tall Aeolis Mons, at the inside the 4,850 metre / 15,900 foot deep and 154 KM / 96 mile wide Gale Crater, within the Aeolis Quadrangle on Mars.
MSL Curiosity remains in superb shape and continues to operate flawlessly.
The afternoon maximum temperture here was a very warm for martian standards minus 6 Celsius / 23 Fahrenheit with a sunrise low of a very mild minus 68 Celsius / minus 90 Fahrenheit. Atmospheric pressure was 7.2 mb. Winds light, sunny by day, clear at night.
100 mm MastCam. Mast Camera.
Navigation Cameras.
Text: Andrew R Brown.
NASA / JPL / Malin Space Science Systems. Mars Science Laboratory Curiosity.
Tuesday 7th April 2020.
Ashford, Kent, United Kingdom.
Venus, with a diameter of 12,104 KM / 7,521 miles and a mass of 4,867.5 billion trillion tons (4,867.5 followed by, twenty zeros tons) was 90.15 million KM / 56.02 million miles from Earth.
Our 3,481 KM / 2,163 mile wide, 74.2 billion trillion ton (74.2 followed by twenty zeros tons) natural satellite the Moon, taken just now. The Pink Full Moon was 356,915 KM / 221,777 miles away from Earth.
Venus appeared close to The Pleiades / Seven Sisters, aka M45. M45 / The Pleiades also known as The Seven Sisters are approximately 385 light years away from the Solar System, so the light we are seeing in 2020 left the heart of the cluster in 1635. The cluster of hot blue B Type stars are thought to be only approximately 100 million years old, barely 2.2% the age of our Solar System. The dinosaurs were beginning to enter their final age on Earth & was about the middle of the Cretaceous period on Earth when the Pleiades formed. The Pleiades may be related to the Tucana – Horologium (a smattering of stars within the southern constellations of Tucana the Toucan and Horologium the Clock) group of similarly aged hot blue stars and their common motion in space as they orbit the centre of the Milky Way suggest a common origin and were once two parts of a much larger cluster. Some of the further stars are about 444 Light years away, light we are seeing in 2020, left them in the year 1591.
The centre of The Pleiades / M45 were about 38.914 million times further away than Venus.
Also got Venus with the Pleiades with the head of Taurus the Bull with the V shaped Hyades cluster, the dying red giant star Aldebaran / Alpha Tauri & just to the left of M45, The Pleiades / Seven Sisters.
The > shape pattern is the central 16 light years of the entire cluster and the centre of the Hyades is approximately 153 light years away from our Solar System, so we are seeing this portion of the cluster in 2020 around the year 1867.
The star at the top right at the end of the V is known as Ain / Epsilon Tauri. Ain / Epsilon Tauri is an ageing Orange Giant star entering the final stages of it's life. With a mass of 2.7 times that of our Sun, Ain / Epsilon Tauri although only approximately 526 million years old is already swelling up into gianthood. Helium in it's core has started to fuse into Oxygen and Carbon with the hydrogen fusing layer extending upwards towards the surface causing the star to swell up and it's surface temperature to cool, the fate of our own Sun in approx. 4 billion years time. Ain / Epsilon Tauri is approximately 12 times wider than the Sun or approx 1,310 times wider than the Earth.
Ain / Epsilon Tauri also has a large massive gas giant planet, some 7.8 times the mass of Jupiter or 2,480 times more massive than Earth. The giant planet orbits Ain / Epsilon Tauri once every 595 days at an average distance of 290 million KM / 180 million miles. This is a good example of a planet in orbit around a dying star.
Aldebaran / Alpha Tauri, the brightest star to the upper left at the end of the V is actually not related to the Hyades at all, but merely lies along the same direction from our viewpoint.
Aldebaran / Alpha Tauri, lies some 65 light years away from our solar system, so is a little less than half the distance to the Hyades. Aldebaran / Alpha Tauri is a dying orange giant star entering the final stages of it's life. With a mass of 1.7 times that of our Sun or about 566,000 times that of the Earth (our Sun has a mass of 332,946 Earths), Aldebaran / Alpha Tauri although only approximately 800 million years old is already swelling up into gianthood. Helium in it's core has started to fuse into Oxygen (free Oxygen created through thermonuclear reactions, not molecular oxygen created by plants through photosynthesis) and Carbon with the hydrogen fusing layer extending upwards towards the surface causing the star to swell up and it's surface temperature to cool, the fate of our own Sun in approximately 4 billion years time.
Aldebaran / Alpha Tauri is approx 44 times wider than the Sun or approximately 4,800 times wider than the Earth (our Sun is 109 times wider than the Earth). Aldebaran / Alpha Tauri is also a slow rotating star, taking 643 days or approx 1 year and 9 months to rotate once as against our Sun's 25 days.
Camera: Canon Powershot SX430 IS.
Taken by: Andrew R Brown.
Main Belt Asteroid / Protoplanet: 2 Pallas.
New images. Southern hemisphere left panel , northern hemisphere right panel.
2 Pallas was discovered on: Sunday 28th March 1802, by Heinrich Wilhelm Matthias Olbers, in Bremen, Germany.
Here is seen the gigantic Main Belt Asteroid 2 Pallas, imaged by the European Southern Observatory, Very Large Telescope / Spectro Polarimetric High-contrast Exoplanet REsearch instrument / SPHERE and the very capable very high resolution adaptive optics system.
Asteroid 2 Pallas is greyish in colour, is a type B, water rick carbon rich asteroid with a mean density of about 2.75 grammes per cubic centimetre and appears to be a solid, coherent object, not a rubble pile held together by gravity.
2 Pallas is 550 KM by 516 KM by 476 KM / 342 by 321 by 296 miles in size.
2 Pallas orbits the Sun once every 4 years, 8 months and 14 days at a mean distance of 416.1 million KM / 258.6 million miles. A very steeply inclined orbit of 34.82 degrees.
2 Pallas is extremely heavily cratered, possibly currently the most heavily cratered large body known, even more so than Main Belt asteroid / protoplanet 1 Ceres, the Jupiter moon Callisto, Saturn moons Rhea, Tethys and Mimas and the Uranus moons Umbriel and Oberon, other large, heavily cratered bodies seen in detail in the solar system.
There are 36 craters, covering 10% of 2 Pallas’s surface, in size between 30 KM to 120 KM / 19 miles to 75 miles wide. Part of this may be due to the strangely highly inclined orbit that 2 Pallas has around the Sun, this increases impact speeds with objects in more normal low inclination orbits to as high as 39,600 KPH / 24,606 MPH, which protoplanets / asteroids 1 Ceres & 4 Vesta do not experience such energetic impacts.
Also in the southern hemisphere, appears a brighter spot, to the left of a large crater with a domed floor, possibly an ice rich, epsom salt outcrop or upwelling much like that within the Occater Crater on protoplanet 1 Ceres.
2 Pallas rotates once every 7 hours & 49 minutes in a retrograde east to west direction.
Resolution. Approximately 18 KM / 11 miles.
Text: Andrew R Brown.
Image Credit: European Southern Observatory. ESO/M. Marsset et al./MISTRAL
Very Large Telescope / Spectro Polarimetric High-contrast Exoplanet REsearch instrument / SPHERE.
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Royal Astronomical Society of New Zealand
Royal Astronomical Society of New Zealand
eNewsletter: No. 232, 20 April 2020
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. Michele Bannister Awarded the 2020 Zeldovich Medal
2. Conference and AGM at Labour Weekend
3. Existing Registrations for 2020 Conference
4. Dark Sky Workshop - new date
5. The Solar System in May
6. Current Brightish Comets
7. 'Eye on the Sky' Video
8. New Zealand Astrophotography Competition - Closes September 21
9. Stargazers Getaway September 18-20
10. 14th Asia-Pacific Regional IAU Meeting Cancelled
11. Communicating Astronomy with the Public Conference
12. Fossil Shells Tell Cretaceous Day Length
13. Katherine Johnson Obituary
14. Neutron Star Size from Gravitational Waves
15. Mid-Size Black Hole Found?
16. How to Join the RASNZ
17. Quotes
1. Michele Bannister Awarded the 2020 Zeldovich Medal
Dr. Michele Bannister of Canterbury University has been awarded the 2020 Zeldovich Medal for the Committee on Space Research (COSPAR) Scientific Commission B.
The Zeldovich Medals are given to young scientists who have demonstrated excellence and achievement in their field of research. They are conferred by COSPAR and the Russian Academy of Sciences and honour the memory of the distinguished astrophysicist Academician Yakov B. Zeldovich.
Michele has been studying the small icy worlds beyond Neptune, co-discovering many of them with the 3.6-m Canada-France-Hawaii Telescope on Maunakea, Hawaii.
See https://cosparhq.cnes.fr/awards/zeldovich-medals/ but the website has not yet been updated with the 2020 award.
2. Conference and AGM at Labour Weekend
Dear RASNZ Members and 2020 Conference Delegates,
RASNZ Council has set the date for the 2020 AGM and Conference for Labour Weekend (23-25 October 2020). Please pencil these new dates into your calendar, noting that these new arrangements are themselves subject to further postponement depending on what restrictions remain on our activities at that time. Council will make further announcements relating to the AGM and Conference as developments arise.
For now, please stay safe within your isolation bubble!
Yours,
Nicholas Rattenbury, President, RASNZ
3. Existing Registrations for 2020 Conference
Those who paid their registration fees for the postponed conference but do not wish to attend the re-scheduled conference over Labour Weekend in October can request a full refund, by emailing the conference organisers (conference@rasnz.org.nz) and providing your bank account details.
Registrants wishing to attend the October Conference need take no action, your registration will remain on record for the rescheduled conference, there being no change to the registration fees.
-- Glen Rowe, Chair, Standing Conference Committee
4. Dark Sky Workshop - new date
A Dark Sky Workshop is planned to follow the re-scheduled RASNZ Conference as announced in the previous item. The workshop will be held, subject to any restrictions that may be in place at the time, on the morning of Monday 26 October2020 (Labour Day). Further details will be made available in due course.
-- Glen Rowe, Chair, Standing Conference Committee
5. 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 9.1
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 7.05am 5.29pm -26.7 Tau 7.33am 5.03pm
Merc -1.8 Ari 6.40am 5.20pm 0.1 Gem 9.30am 6.26pm
Venus -4.7 Tau 10.37am 7.10pm -4.2 Tau 8.10am 5.16pm
Mars 0.4 Cap 12.18am 2.22pm -0.0 Aqr 12.03am 1.18pm
Jup -2.4 Sgr 10.13pm 12.59pm -2.6 Sgr 8.14pm 11.01am
Sat 0.6 Cap 10.38pm 1.15pm 0.4 Cap 8.39pm 11.17am
Uran 5.9 Ari 6.45am 5.18pm 5.9 Ari 4.52am 3.21pm
Nep 7.9 Aqr 2.44am 3.26pm 7.9 Aqr 12.49am 1.30pm
Pluto 14.5 Sgr 10.00pm 12.56pm 14.5 Sgr 8.01pm 10.58am
May 1 NZST May 31 NZST
Twilights morning evening morning evening
Civil: start 6.39am, end 5.56pm start 7.05am, end 5.31pm
Nautical: start 6.07am, end 6.29pm start 6.31am, end 6.06pm
Astro: start 5.34am, end 7.01pm start 5.58am, end 6.39pm
May PHASES OF THE MOON, times NZ & UT
First quarter: May 1 at 8.38am (Apr 30, 20:38 UT)
Full Moon: May 7 at 10.45pm (10:45 UT)
Last quarter: May 15 at 2.03am (May 14, 14:03 UT)
New Moon: May 23 at 5.39am (May 22, 17:39 UT)
First quarter: May 30 at 3.30pm (03:30 UT)
PLANETS in MAY
MERCURY is at superior conjunction with the Sun on May 4. Following conjunction, it becomes an evening planet. By the end of May the planet sets some 80 minutes after the Sun. A little before 6pm, towards the end of May, it may be visible very low to the north-west.
VENUS, as an evening object, sets about 100 minutes after the Sun at the beginning of May. It will then be visible as a brilliant object rather low to the north-west soon after sunset. The elongation of Venus steadily decreases during May, especially after it is stationary on the 13th. By the 31st it will be only 5° from the Sun so unobservable.
Venus and Mercury are less than a degree apart on May 22. They will be very difficult to see, requiring a clear low horizon. Half an hour after sunset Venus will be only 2° up with Mercury to its upper left.
JUPITER and SATURN are about 5° apart throughout May. Saturn is stationary on the 11th, Jupiter on the 15th (NZ time). Hence both will be slow moving all month. The moon joins the two planets on the night of 12/13 May. It is about 3° from each planet about 1am.
PLUTO is 2° from Jupiter on the opposite side to Saturn.
MARS rises shortly after midnight. It moves to the east away from Jupiter and Saturn during May, crossing from Capricornus to Aquarius on the 8th. On May 16 the moon, near last quarter, will be 5° to the left of Mars an hour before sunrise.
URANUS moves up into the morning sky during May. It is too close to the Sun for observation early in the month, but by the end of May it will rise more than two and a half hours before the Sun. NEPTUNE, also a morning object, rises 4 hours before Uranus.
POSSIBLE BINOCULAR ASTEROIDS in MAY
May 1 NZST May 31 NZST
Mag Cons transit Mag Cons transit
(1) Ceres 9.2 Aqr .8.09am 9.0 Aqr 6.44am
(4) Vesta 8.5 Tau 2.43pm 8.4 Ori 1.39pm
CERES is a morning object. It rises at 1am on the 1st and 11.37pm on the 31st.
VESTA is an evening object getting low by the end of May. It sets at 7.30 pm NZST on the 1st and 6.18 pm on the 31st. Vesta is about 5° from Venus mid May and moves from Taurus to Orion on the 29th.
-- Brian Loader
6. Current Brightish Comets
Binocular Comet C/2020 F8 (SWAN)
This comet was seen by M. Mattiazzo on images from the Solar Wind Anisotropies (SWAN) camera on the Solar and Heliospheric
Observer (SOHO) spacecraft. Numerous ground-based observations followed.
A preliminary parabolic orbit by S. Nakano gives the comet's perihelion at 2020 May 27.5 TT at a distance of 0.4309 AU (65 million km) from the Sun. The comet is 0.555 AU (83 million km) from Earth on May 15. On current predictions the comet will be at its brightest at the end of May. Unfortunately it will be below NZ's northern horizon then.
Below are positions of C/2020 F8 (SWAN) at 6 a.m. NZST. m1 is the total magnitude, the magnitude of a star defocused to the comet's size. An m1 fainter than 3 is not easily seen by eye.
Apr. R.A.(2000)Dec. m1 May R.A.(2000)Dec. m1
h m ° ' h m ° '
21 23 20.0 -31 00 7.9 01 23 56.7 -17 44 6.3
22 23 22.9 -30 03 7.8 02 00 01.6 -15 46 6.1
23 23 26.0 -29 03 7.7 03 00 06.8 -13 37 6.0
24 23 29.1 -27 59 7.5 04 00 12.5 -11 17 5.8
25 23 33.0 -26 49 7.3 05 00 18.5 -08 47 5.6
26 23 36.0 -25 35 7.2 06 00 25.0 -06 04 5.4
27 23 39.7 -24 15 7.0 07 00 31.9 -03 09 5.2
28 23 43.5 -22 48 6.8 08 00 39.4 -00 03 5.1
29 23 47.7 -21 15 6.7 09 00 47.4 +03 15 4.9
30 23 52.0 -19 34 6.5 10 00 56.0 +06 42 4.7
11 01 05.3 +10 17 4.6
12 01 15.2 +13 57 4.4
13 01 25.7 +17 39 4.3
14 01 37.0 +21 17 4.2
15 01 48.8 +24 50 4.1
16 02 01.3 +28 12 4.0
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Comet Atlas (C/2019 Y4)
There has been much northern hemisphere interest in this comet as it appeared that it might be bright at perihelion at the end of May. It would have been below NZ's north horizon then, as it is now.
The comet faded in March and images obtained in April show that it is breaking up. The nucleus, the solid part, has fragmented into at least four pieces. This isn't too surprising as C/2019 Y4 is itself a fragment of a larger comet. It is in the same orbit as the Great Comet C/1844 Y1. Both comets have an orbital period of around 4000 years so C/2019 Y4 can't be a reappearance of C/1844 Y1. It'll be interesting to see if C/2019 Y4
even gets to perihelion before it fragments completely.
7. 'Eye on the Sky' Video
John Drummond has produced his first 'Eye on the NZ Sky' video on Venus as part of the RASNZ initiative to promote astronomy through the Lockdown. John has kept it under 10-minutes length and has made it beginner/child and naked eye friendly.
There were many teething issues and challenges in producing this initial videos. There will be other regular videos in this series and the quality will be much better.
Here's the link -
https://www.youtube.com/watch?v=fZxVhDxxIqE
-- Nalayini Brito
8. New Zealand Astrophotography Competition - Closes September 21
Entries are sought for the 2020 New Zealand Astrophotography competition.
The competition is fully endorsed by the Royal Astronomical Society of New Zealand and is the nation's largest astrophotography competition.
See last month's Newsletter for details.
The competition cut-off date is the 21st of September and the competition awards will be announced at the annual Burbidge dinner which is the Auckland Astronomical Society's premier annual event, keep an eye out on the society website for details on the forthcoming Burbidge dinner.
You can find the rules and entry forms on the AAS website at https://www.astronomy.org.nz/new/public/default.aspx
-- From Jonathan Green's posting nnzastronomers Yahoo group
9. Stargazers Getaway September 18-20
Stargazers Getaway 2020 at Camp Iona on Friday September 18th to Sunday 20th. This is New Moon, so we are targeting this weekend for dark skies! Camp Iona is near Herbert, south of Oamaru.
See last month's Newsletter for details and
https://www.facebook.com/events/943327669369996/
10. 14th Asia-Pacific Regional IAU Meeting Cancelled
The 14th Asia-Pacific Regional IAU Meeting that was to be held in Perth, Western Australia, on July 6 - 10, 2020 has been cancelled due to the covid-19 pandemic. See statement on meeting's website at
www.aprim2020.org .
11. Communicating Astronomy with the Public Conference
From 21 to 25 September 2020, Macquarie University in Sydney, Australia, and the International Astronomical Union (IAU) Commission C2 - Communicating Astronomy with the Public (CAP), will host the world's largest conference on astronomy communication: Communicating Astronomy with the Public 2020 (CAP2020). Professionals from science communication, informal education, planetaria and science centres, as well as professional and amateur astronomers, journalists and creatives, are invited to attend the conference to exchange ideas and discuss best practice.
See last month's Newsletter for details, also
https://www.communicatingastronomy.org/cap2020/
The website now says "Abstract & grant applications deadline extended until 30 April 2020." It also notes that the CAP 2020 organisers are closely monitoring the Covid-19 outbreak.
12. Fossil Shells Tell Cretaceous Day Length
It has long been known that the Earth's rotation is slowing down. Growth rings on fossil shells show that that the number of days in a lunar month, via tide cycles, and the number of days in a year have become less as the day lengthens.
New results from fossil mollusc shells from the late Cretaceous have added much more detail. The new study analysed a single individual that lived for over nine years in a shallow seabed in the tropics — a location which is now, 70-million-years later, dry land in the mountains of Oman.
The new method focused a laser on small bits of shell, making holes 10 microns in diameter, or about as wide as a red blood cell. Trace elements in these tiny samples reveal information about the temperature and chemistry of the water at the time the shell formed. The analysis provided accurate measurements of the width and number of daily growth rings as well as seasonal patterns. The researchers used seasonal variations in the fossilized shell to identify years. The study was led by Niels de Winter, an analytical geochemist at Vrije Universiteit Brussel.
The new study found the composition of the shell changed more over the course of a day than over seasons, or with the cycles of ocean tides. The fine-scale resolution of the daily layers shows the shell grew much faster during the day than at night.
This result suggests daylight was more important to the lifestyle of the ancient mollusc than might be expected if it fed itself primarily by filtering food from the water, like modern day clams and oysters, according to the authors. De Winter said the molluscs likely had a relationship with an indwelling symbiotic species that fed on sunlight, similar to living giant clams, which harbour symbiotic algae.
De Winter’s careful count of the number of daily layers found 372 for each yearly interval. This was not a surprise, because scientists know days were shorter in the past. The result is, however, the most accurate now available for the late Cretaceous, and has a surprising application to modelling the evolution of the Earth-Moon system.
The length of a year has been constant over Earth’s history, because Earth’s orbit around the Sun does not change. But the number of days within a year has been shortening over time because days have been growing longer. The length of a day has been growing steadily longer as friction from ocean tides, caused by the Moon’s gravity, slows Earth’s rotation.
The pull of the tides accelerates the Moon a little in its orbit, so as Earth’s spin slows, the Moon moves farther away. The moon is pulling away from Earth at 3.82 cm per year. Precise laser measurements of distance to the Moon from Earth have demonstrated this increasing distance since the Apollo program left helpful reflectors on the Moon’s surface.
The Moon’s rate of retreat has changed over time, and information from the past, like a year in the life of an ancient clam, helps researchers reconstruct that history and model of the formation of the moon. Because in the history of the Moon, 70 million years is a blink in time, de Winter and his colleagues hope to apply their new method to older fossils and catch snapshots of days even deeper in time.
-- From an American Geological Union AGU (www.agu.org) press release forwarded by Karen Pollard. The lengthy press release is no longer available on-line but the Newsletter editor is happy to forward it on request. The original paper can be seen at
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019PA003723
13. Katherine Johnson Obituary
As she ran her eyes over the flight-test calculation sheets the engineer had given her, Katherine Goble (as she then was) could see there was something wrong with them. The engineer had made an error with a square root. And it was going to be tricky to tell him so. It was her first day on this assignment, when she and another girl had been picked out of the computing pool at the Langley aeronautical laboratory, later part of NASA, to help the all-male Flight Research Unit. But there were other, more significant snags than simply being new.
Most obviously, he was a man and she was a woman. In 1953 women did not question men. They stayed in their place, in this case usually the computing pool, tapping away on their Monroe desktop calculators or filling sheets with figures, she as neatly turned out as all the rest. Men were the grand designers, the engineers; the women were “computers in skirts”, who were handed a set of equations and exhaustively, diligently checked them. Men were not interested in things as small as that.
And, most difficult of all, she was Coloured, and he was White. The lab might be recruiting black mathematicians, but the door was not fully open; her pool was called “Coloured Computing”, and was segregated. As she sat down with the new team that morning, the men next to her had moved away. She was not sure why, but the world was like that, and she refused to be bothered by it. Since the café was segregated, she ate at her desk. There was no Coloured restroom, so she used the White one. A few years back, when the bus taking her to her first teaching job in Marion, Virginia, had crossed the state line from West Virginia, all the blacks had been told to get off and take taxis. She refused until she was asked nicely. But it could be unwise to push a white man too far.
Nonetheless, this engineer’s calculation was wrong. If she did not ask the question, an aircraft might not fly, or might fly and crash. So, very carefully, she asked it. Was it possible that he could have made a mistake? He did not admit it but, by turning the colour of a cough drop, he ceded the point.
She asked more such questions, and they got her noticed. As the weeks passed, the men “forgot” to return her to the pool. Her incessant “Why?” and “How?” made their work sharper. It also challenged them. Why were their calculations of aerodynamic forces so often out? Because they were maths graduates who had forgotten their geometry, whereas she had not; her high-school brilliance at maths had led to special classes on analytic geometry in which she, at 13, had been the only pupil. Why was she not allowed to get her name on a flight-trajectory report when she had done most of the work, filling her data sheets with figures for days? Because women didn’t. That was no answer, so she got her name on the report, the first woman to be so credited. Why was she not allowed into the engineers’ lectures on orbital mechanics and rocket propulsion? Because “the girls don’t go”. Why? Did she not read Aviation Week, like them? She soon became the first woman there.
As NASA’s focus turned from supersonic flight to flights in space, she was therefore deeply involved, though still behind the scenes. This excited her, because if her first love was mathematics — counting everything as a child, from plates to silverware to the number of steps to the church — her second was astronomy, and the uncountable stars. A celestial globe now joined the calculator on her desk. She had to plot the trajectories of spacecraft, developing the launch window and making sure — as soon as humans took off — that the module could get back safely. This involved dozens of equations to calculate, at each moment, which bit of Earth the spacecraft was passing over, making allowances for the tilt of the craft and the rotation of the planet. She ensured that Alan Shepard’s Mercury capsule splashed down where it could be found quickly in 1961, and that John Glenn in 1962 could return safely from his first orbits of the Earth. Indeed, until “the girl”, as he called her (she was 43), had checked the figures by hand against those of the newfangled electronic computer, he refused to go.
That checking took her a day and a half. Later she calculated the timings for the first Moon landing (with the astronauts’ return), and worked on the Space Shuttle. She also devised a method by which astronauts, with one star observation checked against a star chart, could tell where they were. But in the galaxy of space-programme heroes, despite her 33 years in the Flight Research Unit, for a long time she featured nowhere.
It did not trouble her. First, she also had other things to do: raise her three daughters, cook, sew their clothes, care for her sick first husband. Second, she knew in her own mind how good she was — as good as anybody. She could hardly be unaware of it, when she had graduated from high school at 14 and college at 18, expert at all the maths anyone knew how to teach her. But she typically credited the help of other people, especially her father, the smartest man she knew, a farmer and a logger, who could look at any tree and tell how many board-feet he could get out of it; and who had sold the farm and moved the family so that she and her siblings could all get a fine schooling and go to college. And last, at NASA, she had not worked alone. She had been one of around a dozen black women mathematicians who were equally unknown. But when their story emerged in the 21st century, most notably in a book and a film called “Hidden Figures”, she had a NASA building named after her, a shower of honorary doctorates and — the greatest thrill — a kiss from Barack Obama as he presented her, at 96, with the Presidential Medal of Freedom.
This attention was all the more surprising because, for her, the work had been its own reward. She just did her job, enjoying every minute. The struggles of being both black and a woman were shrugged away. Do your best, she always said. Love what you do. Be constantly curious. And learn that it is not dumb to ask a question; it is dumb not to ask it. Not least, because it might lead to the small but significant victory of making a self-proclaimed superior realise he can make a mistake.
Katherine Johnson died on February 24th aged 101.
-- This article appeared in the Obituary section of the print edition of The Economist February 27th 2020, page 74, under the headline "The girl who asked questions"
14. Neutron Star Size from Gravitational Waves
Scientists have combined observations of gravitational waves from a neutron star collision with nuclear theory to shed light on the size and nature of neutron stars.
Neutron stars, the collapsed cores of massive stars, compress matter so tightly that atoms break apart and nearly everything converts into neutrons. As a result, about 1½ Suns’ worth of mass squeezes into these Manhattan-size objects. Most of this matter, perhaps all of it, is in the form of neutrons, but some theories suggest that deep within neutron stars, neutrons themselves dissociate, leaving a soup of quarks and gluons.
There’s no way to peer inside a neutron star, of course. But their size betrays their interior — the smaller a neutron star, the more it compresses its innards. So by taking a ruler to neutron stars, scientists can probe their nature.
In a study appearing March 9th in Nature Astronomy, Collin Capano (Max Planck Institute for Gravitational Physics and Leibniz University Hannover, Germany) and colleagues examine the ripples in spacetime released in a neutron star merger. Combining these gravitational-wave observations with nuclear theory, the scientists estimate that a typical neutron star would span about 22 km.
This is the most precise measurement obtained from gravitational waves, and it has important implications for future observations.
The Laser Interferometer Gravitational-wave Observatory (LIGO) detectors witnessed spacetime ripples coming from two colliding neutron stars on August 17, 2017. The event, known as GW170817, marked the first time that astronomers could see both light and gravitational waves coming from the same source.
While the gravitational-wave signal showed the neutron stars spiralling inward and merging into a single object, light released across the electromagnetic spectrum showed the aftereffect — an explosion known as a kilonova that was visible from 130 million light-years away. At the centre of the explosion, observations suggest a short-lived “hypermassive” neutron star formed that then collapsed into a black hole.
To understand the nature of the neutron stars that collided, Capano and colleagues wielded mathematics describing the nature of neutron star material, known as an equation of state. After folding in the gravitational-wave and electromagnetic observations, the equation yields the size of a typical neutron star: between 20.8 and 23.8 km across. This estimate is twice as precise as previous results.
“Like we've seen in other results from analysing GW170817, gravitational-wave astronomy has begun to meaningfully constrain the range of possibilities for neutron star matter,” says Jocelyn Read (California State University, Fullerton). “It suggests neutron stars are on the compact side.”
More compact neutron stars might mean more exotic interiors. But Read cautions that it’s not quite that simple. Even larger sizes could accommodate quark-soup cores, while smaller sizes could still be “boring” mostly-neutron objects.
Capano agrees. “We just don’t have enough data at the moment to say conclusively what happens in the core,” he says.
More gravitational-wave events will help, Capano adds, as will ongoing observations from the Neutron Star Interior Composition Explorer (NICER) instrument aboard the International Space Station. Upcoming physics experiments will also play a role in better nailing down the nuclear theory.
Meanwhile, the compact nature of neutron stars has immediate implications for gravitational-wave observations of encounters between neutron stars and black holes. A smaller, more tightly packed neutron star would be more difficult for a black hole to tear apart before pulling it in, so black holes are more likely to swallow neutron stars whole.
That means that if a black hole and a neutron star collide, we wouldn’t expect any light-emitting counterpart — astronomers would have to rely on gravitational-wave signals alone. Only if the black hole were exceedingly small or spinning rapidly would any light be produced, Capano explains.
Nevertheless, advances in our understanding of neutron stars are on the horizon. The LIGO Collaboration, as well as the Virgo Collaboration in Italy, are analysing results from gravitational-wave signals detected since April 2019. Their list of bona fide events, expected at the end of April 2020, should include multiple black hole mergers and at least one neutron star collision.
-- Monica Young's article on https://skyandtelescope.org/astronomy-news/gravitational-waves-put-ruler-to-neutron-stars/
15. Mid-Size Black Hole Found?
New data from the NASA/ESA Hubble Space Telescope have provided the strongest evidence yet for mid-sized black holes in the Universe. Hubble confirms that this “intermediate-mass” black hole dwells inside a dense star cluster.
Intermediate-mass black holes (IMBHs) are a long-sought “missing link” in black hole evolution. There have been a few other IMBH candidates found to date. They are smaller than the supermassive black holes that lie at the cores of large galaxies, but larger than stellar-mass black holes formed by the collapse of massive stars. This new black hole is over 50 000 times the mass of our Sun.
IMBHs are hard to find. “Intermediate-mass black holes are very elusive objects, and so it is critical to carefully consider and rule out alternative explanations for each candidate. That is what Hubble has allowed us to do for our candidate,” said Dacheng Lin of the University of New Hampshire, principal investigator of the study.
Lin and his team used Hubble to follow up on leads from NASA’s Chandra X-ray Observatory and the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton), which carries three high-throughput X-ray telescopes and an optical monitor to make long uninterrupted exposures providing highly sensitive observations.
“Adding further X-ray observations allowed us to understand the total energy output,” said team member Natalie Webb of the Université de Toulouse in France. “This helps us to understand the type of star that was disrupted by the black hole.”
In 2006 these high-energy satellites detected a powerful flare of X-rays, but it was not clear if they originated from inside or outside of our galaxy. Researchers attributed it to a star being torn apart after coming too close to a gravitationally powerful compact object, like a black hole.
Surprisingly, the X-ray source, named 3XMM J215022.4?055108, was not located in the centre of a galaxy, where massive black holes normally reside. This raised hopes that an IMBH was the culprit, but first another possible source of the X-ray flare had to be ruled out: a neutron star in our own Milky Way galaxy, cooling off after being heated to a very high temperature. Neutron stars are the extremely dense remnants of an exploded star.
Hubble was pointed at the X-ray source to resolve its precise location. Deep, high-resolution imaging confirmed that the X-rays emanated not from an isolated source in our galaxy, but instead in a distant, dense star cluster on the outskirts of another galaxy — just the sort of place astronomers expected to find evidence for an IMBH. Previous Hubble research has shown that the more massive the galaxy, the more massive its black hole. Therefore, this new result suggests that the star cluster that is home to 3XMM J215022.4?055108 may be the stripped-down core of a lower-mass dwarf galaxy that has been gravitationally and tidally disrupted by its close interactions with its current larger galaxy host.
IMBHs have been particularly difficult to find because they are smaller and less active than supermassive black holes. They do not have readily available sources of fuel, nor do they have a gravitational pull that is strong enough for them to be constantly drawing in stars and other cosmic material and producing the tell-tale X-ray glow. Astronomers therefore have to catch an IMBH red-handed in the relatively rare act of gobbling up a star. Lin and his colleagues combed through the XMM-Newton data archive, searching hundreds of thousands of sources to find strong evidence for this one IMBH candidate. Once found, the X-ray glow from the shredded star allowed astronomers to estimate the black hole’s mass.
Confirming one IMBH opens the door to the possibility that many more lurk undetected in the dark, waiting to be given away by a star passing too close. Lin plans to continue this meticulous detective work, using the methods his team has proved successful.
“Studying the origin and evolution of the intermediate mass black holes will finally give an answer as to how the supermassive black holes that we find in the centres of massive galaxies came to exist,” added Webb.
Black holes are one of the most extreme environments humans are aware of, and so they are a testing ground for the laws of physics and our understanding of how the Universe works. Does a supermassive black hole grow from an IMBH? How do IMBHs themselves form? Are dense star clusters their favoured home? With a confident conclusion to one mystery, Lin and other black hole astronomers find they have many more exciting questions to pursue.
-- From the Hubble Space Telescope press release forwarded by Karen Pollard. See the original at https://www.spacetelescope.org/news/heic2005/
16. 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 2020 year starts at $40 for an ordinary
member, which includes an electronic subscription to our journal
'Southern Stars'.
17. Quotes
"Dwell on the beauty of life. Watch the stars, and see yourself running with them." Marcus Aurelius, Roman Emperor and Stoic philosopher (121-180). From The Otago Daily Times.
"Just as we are asking our frail, vulnerable, easily confused old people to stay indoors, America is being asked to put them in the White House." -- UK Times writer Matt Chorley quoted in The Listener.
"Please note: The post-apocalyptical fiction section has been moved to Current Affairs." -- Book shop notice posted on Facebook.
"Here's a very appropriate analogy: 'The curve is flattening; we can start lifting restrictions now' = 'The parachute has slowed our rate of descent; we can take it off now.'" -- Seen on Facebook.
Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
--------------------------------------------------------------------------------
You can view updated paths and other details at:
http://www.occultations.org.nz/
Minor Planet Occultation Updates:
================================
This email describes updates for minor planet occultations for April 2020.
If you do not wish to receive these updates please advise
the Occultation Section.
You can view updated paths and other details at:
http://www.occultations.org.nz/
Minor Planet Occultation Updates:
================================
Events of particular ease or importance below are marked: *****
***** Apr 1 (1841) MASARYK: Star Mag 10.1, Max dur 2.2 sec, Mag Drop 7.2
Somewhat uncertain path across the North Island of New Zealand, passing near Auckland and over Whakatane.
Details: http://occultations.org.nz/planet/2020/updates/200401_1841_67140_u.htm
Apr 2 (85) IO: Star Mag 11.9, Max dur 14.6 sec, Mag Drop 0.9
Path across West Australia, passing over Geraldton.
Details: http://occultations.org.nz/planet/2020/updates/200402_85_64596_u.htm
Apr 3 (347) PARIANA: Star Mag 11.1, Max dur 4.4 sec, Mag Drop 2.7
West Australia, Northern Territory, Queensland and New South Wales, passing over Alice Springs, Birdsville, Coonabarrabran and Newcastle.
Details: http://occultations.org.nz/planet/2020/updates/200403_347_64602_u.htm
Apr 4 2015KP173: No update for this TNO event
Apr 4 (546) HERODIAS: Star Mag 11.4, Max dur 6.2 sec, Mag Drop 3.3
Northern West Australia, Northern Territory and South Australia, passing over Port Augusta, Adelaide and Mount Gambier.
Details: http://occultations.org.nz/planet/2020/updates/200404_546_64622_u.htm
Apr 5 (85) IO: Star Mag 12.3, Max dur 15.8 sec, Mag Drop 0.7
Central-western West Australia, passing over Geraldton, during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200405_85_64632_u.htm
Apr 6 (559) NANON: Star Mag 11.9, Max dur 2.6 sec, Mag Drop 3.3
South Northern Territory and southern Queensland and north-eastern New South Wales, passing over Byron Bay.
Details: http://occultations.org.nz/planet/2020/updates/200406_559_68086_u.htm
***** Apr 7 (1690) MAYRHOFER: Star Mag 10.4, Max dur 3.5 sec, Mag Drop 5.9
Somewhat uncertain path across Queensland, Northern Territory and New Zealand, passing near Caloundra and Taupo.
Details: http://occultations.org.nz/planet/2020/updates/200407_1690_67142_u.htm
Apr 7 (1194) ALETTA: Star Mag 11.0, Max dur 7.0 sec, Mag Drop 3.3
Slightly uncertain path across south-eastern New South Wales, central Victoria, southern South Australia and south-western West Australia, passing over Kilmore, Kingston SE and Waroona.
Details: http://occultations.org.nz/planet/2020/updates/200407_1194_64644_u.htm
Apr 8 (454) MATHESIS: Star Mag 12.0, Max dur 4.2 sec, Mag Drop 2.3
West Australia, Northern Territory and Queensland, during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200408_454_64656_u.htm
***** Apr 10 (66) MAJA: Star Mag 11.3, Max dur 20.7 sec, Mag Drop 2.8
Path across New Zealand, passing over Auckland and Coromandel.
Details: http://occultations.org.nz/planet/2020/updates/200410_66_64666_u.htm
Apr 10 (480) HANSA: Star Mag 10.4, Max dur 2.8 sec, Mag Drop 1.0
Central West Australia, Northern Territory, northern South Australia and Queensland, passing Kalbarri, Birdsville and Maryborough.
Details: http://occultations.org.nz/planet/2020/updates/200410_480_67144_u.htm
Apr 11 (92) UNDINA: Star Mag 12.1, Max dur 10.1 sec, Mag Drop 0.6
New Zealand, northern Victoria, South Australia and West Australia, passing over Dunedin, Alexandra, Orbost, Benalla, Echuca and Whyalla.
Details: http://occultations.org.nz/planet/2020/updates/200411_92_64674_u.htm
Apr 11 (159) AEMILIA: Star Mag 11.3, Max dur 11.4 sec, Mag Drop 1.8
Queensland, Northern Territory and West Australia, passing over Ingham, Townsville, Cardwell and Wyndham.
Details: http://occultations.org.nz/planet/2020/updates/200411_159_64676_u.htm
***** Apr 12 (6392) TAKASHIMIZUNO: Star Mag 8.7, Max dur 0.7 sec, Mag Drop 8.5
Significantly uncertain path across West Australia, southern South Australia, northern Victoria, southern New South Wales and New Zealand, passing over Ceduna, Swan Hill, Eden and near Wellington during late morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200412_6392_68096_u.htm
Apr 13 (626) NOTBURGA: Marginal event during late morning twilight mostly over Tasman Sea.
***** Apr 14 (1691) OORT: Star Mag 8.8, Max dur 1.2 sec, Mag Drop 7.8
Somewhat uncertain path across West Australia, South Australia and New South Wales, passing over Carnarvon, Wagga Wagga, Narooma and Bermagui.
Details: http://occultations.org.nz/planet/2020/updates/200414_1691_67150_u.htm
Apr 14 (312) PIERRETTA: Star Mag 12.3, Max dur 8.9 sec, Mag Drop 0.9
Somewhat uncertain path across central Queensland, north-western New South Wales and central South Australia, passing near Sarina, Mackay, Port Pirie and Maitland.
Details: http://occultations.org.nz/planet/2020/updates/200414_312_64696_u.htm
Apr 15 (954) LI: Star Mag 12.5, Max dur 4.6 sec, Mag Drop 2.1
Slightly uncertain path across New Zealand, New South Wales, northern South Australia and central West Australia, passing over Wanganui, Sydney, Bathurst, Parkes and Karratha.
Details: http://occultations.org.nz/planet/2020/updates/200415_954_64706_u.htm
***** Apr 15 (1288) SANTA: Star Mag 9.2, Max dur 3.2 sec, Mag Drop 6.8
Somewhat uncertain path across South Island of New Zealand and southern Tasmania, passing over Christchurch and Hobart.
Details: http://occultations.org.nz/planet/2020/updates/200415_1288_67152_u.htm
Apr 15 (1116) CATRIONA: Star Mag 11.0, Max dur 4.7 sec, Mag Drop 4.7
Somewhat uncertain path across western Queensland and eastern South Australia, running from Weipa to Murray Bridge.
Details: http://occultations.org.nz/planet/2020/updates/200415_1116_64708_u.htm
Apr 17 2003HF57: No update for this unnumbered Centaur event.
Apr 17 (1771) MAKOVER: Star Mag 12.1, Max dur 14.5 sec, Mag Drop 4.0
Somewhat uncertain path across northern Queensland and New Zealand, passing over Cape Melville and Wellington.
Details: http://occultations.org.nz/planet/2020/updates/200417_1771_64726_u.htm
Apr 18 (69) HESPERIA: Star Mag 11.7, Max dur 5.5 sec, Mag Drop 0.9
Path across south-eastern Queensland, during evening twilight.
Details: http://occultations.org.nz/planet/2020/updates/200418_69_64730_u.htm
Apr 18 (105) ARTEMIS: Star Mag 11.9, Max dur 5.2 sec, Mag Drop 2.0
South Australia, north-western Victoria and central New South Wales, passing over Adelaide, Murray Bridge, Mildura, Parkes and Taree.
Details: http://occultations.org.nz/planet/2020/updates/200418_105_64732_u.htm
***** Apr 18 (389) INDUSTRIA: Star Mag 10.6, Max dur 3.4 sec, Mag Drop 2.5
West Australia, northern South Australia and central New South Wales, passing over Onslow, Broken Hill, Goulburn and Ulladulla.
Details: http://occultations.org.nz/planet/2020/updates/200418_389_64734_u.htm
Apr 19 (1282) UTOPIA: Star Mag 12.5, Max dur 5.2 sec, Mag Drop 3.1
Somewhat uncertain path across Queensland, northern South Australia and southern West Australia, passing near Rockhampton, Kalgoorlie and Perth.
Details: http://occultations.org.nz/planet/2020/updates/200419_1282_64740_u.htm
Apr 19 (1145) ROBELMONTE: Star Mag 11.0, Max dur 2.7 sec, Mag Drop 3.1
Somewhat uncertain path across Queensland, Northern Territory and northern West Australia, running from Marlborough to Karratha.
Details: http://occultations.org.nz/planet/2020/updates/200419_1145_68104_u.htm
Apr 19 (1977) SHURA: Star Mag 11.7, Max dur 18.0 sec, Mag Drop 4.1
Large uncertainty path across eastern West Australia.
Details: http://occultations.org.nz/planet/2020/updates/200419_1977_64744_u.htm
Apr 21 (554) PERAGA: Star Mag 11.0, Max dur 6.9 sec, Mag Drop 3.1
Central West Australia, northern South Australia and southern Queensland, running from Shark Bay to Caboolture.
Details: http://occultations.org.nz/planet/2020/updates/200421_554_64756_u.htm
***** Apr 22 (1159) GRANADA: Star Mag 8.3, Max dur 3.3 sec, Mag Drop 6.6
Somewhat uncertain path across southern New South Wales, north-western Victoria, southern South Australia and south-western West Australia, passing over Wollongong, Swan Hill, Kangaroo Island and Albany.
Details: http://occultations.org.nz/planet/2020/updates/200422_1159_67026_u.htm
Apr 22 (670) OTTEGEBE: Star Mag 8.0, Max dur 9.3 sec, Mag Drop 6.4
Slightly uncertain path across eastern West Australia, running from Point Culver to Broome.
Details: http://occultations.org.nz/planet/2020/updates/200422_670_67028_u.htm
***** Apr 23 (99) DIKE: Star Mag 12.3, Max dur 7.1 sec, Mag Drop 1.1
Eastern areas of New Zealand's North and South Islands, passing over Gisborne, Wellington, Christchurch and Dunedin.
Details: http://occultations.org.nz/planet/2020/updates/200423_99_64768_u.htm
Apr 23 (165) LORELEY: Star Mag 11.9, Max dur 6.2 sec, Mag Drop 1.7
South Australia, then across north-western Victoria and New South Wales, passing over Adelaide, Mildura and Dubbo during morning twilight.
Details: http://occultations.org.nz/planet/2020/updates/200423_165_64770_u.htm
Apr 24 (389) INDUSTRIA: Star Mag 12.3, Max dur 3.1 sec, Mag Drop 1.2
Path across New South Wales during evening twilight then across New Zealand, passing over Westport.
Details: http://occultations.org.nz/planet/2020/updates/200424_389_64776_u.htm
***** Apr 24 (779) NINA: Star Mag 8.9, Max dur 21.5 sec, Mag Drop 3.5
Southern New South Wales, north-western Victoria, South Australia and southern West Australia, passing over Nowra, Wagga Wagga, Maitland and Jurien.
Details: http://occultations.org.nz/planet/2020/updates/200424_779_64778_u.htm
Apr 25 (322) PHAEO: Marginal event that will cross NZ south island shortly before sunrise.
Apr 25 (546) HERODIAS: Star Mag 11.6, Max dur 8.8 sec, Mag Drop 2.8
Slightly uncertain path across eastern Northern Territory and western South Australia, passing over Tennant Creek and Alice Springs.
Details: http://occultations.org.nz/planet/2020/updates/200425_546_64788_u.htm
Apr 25 (471325) 2011KT19: No update for this TNO event over western Australia.
Apr 26 (186) CELUTA: Star Mag 11.8, Max dur 6.7 sec, Mag Drop 1.1
Somewhat uncertain path across Queensland, western New South Wales, extreme north-western Victoria and south-eastern South Australia, running from Bowen to Kingston SE.
Details: http://occultations.org.nz/planet/2020/updates/200426_186_64796_u.htm
Apr 28 (120) LACHESIS: Star Mag 9.8, Max dur 12.1 sec, Mag Drop 3.6
path across Northern Territory and Queensland, passing over Cloncurry and Mount Isa.
Details: http://occultations.org.nz/planet/2020/updates/200428_120_64804_u.htm
Note: for some events there will be an additional last minute update so check
for one, if you can, on the day of the event or in the days leading up to it.
You may need to click "Reload" or "Refresh" in your browser to see the updated page.
Please report all attempts at observation to the address below.
(PLEASE report observations on a copy of the report available from our website).
Peter Litwiniuk
---------------------------------------------
RASNZ Occultation Section
P.O.Box 3181 / Wellington, 6140 / New Zealand
---------------------------------------------
WEBSITE: http://www.occultations.org.nz/
Email: Director@occultations.org.nz
---------------------------------------------
---------------------------------------------
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Further links and discussion can be found at the groups/links below
Astronomy in New Zealand - Groups.io
https://groups.io/g/AstronomyNZ
Astronomy in New Zealand - Facebook
https://www.facebook.com/groups/5889909863/
Astronomy in Wellington
https://www.facebook.com/groups/11451597655/
Blogger Posts
http://laintal.blogspot.com/
https://twitter.com/Laintal
Groups.io
Astronomy in New Zealand
https://groups.io/g/AstronomyNZ
AstronomyNZ@groups.io
Wellington Astronomers
https://groups.io/g/WellingtonAstronomers
WellingtonAstronomers@groups.io
AucklandAstronomers
https://groups.io/g/AucklandAstronomers
AucklandAstronomers@groups.io
North Island Astronomers
https://groups.io/g/NorthIslandAstronomers
NorthIslandAstronomers@groups.io
South Island Astronomers
https://groups.io/g/SouthIslandAstronomers
SouthIslandAstronomers@groups.io
NZAstrochat
https://groups.io/g/NZAstrochat
NZAstrochat@groups.io
NZ Photographers And Observers
https://groups.io/g/NZPhotographers
NZPhotographers@groups.io
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Please note:
My standard caveat that these are the views of a learned amateur, not a professional in the sector, applies as always.
The above post/email/update represents my own words, views, research and opinions, unless stated otherwise the above work
represents my own writing. I’ll give credit or thanks if I have used or represented other people’s words and/or opinions.
The links and references listed below represent the work and research of the respective author’s.
Questions and constructive criticism are always welcome, however I don’t believe anything written here by myself is any reason for impolite behaviour.
Thanks for your time and I hope you have enjoyed reading.
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