January 2021 News and Research
Astronomy_News_20_01_2021
This months research Papers 20_01_2021
RASNZ_20_01_2021
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
Google Group
https://groups.google.com/g/nzastrochat
Astronomy in Wellington
https://www.facebook.com/groups/11451597655/
Blogger Posts
http://laintal.blogspot.com/
Reddit
https://www.reddit.com/user/Edwin_Rod_NZ
Quaroa
https://www.quora.com/q/astronomyinnewzealand
Twitter
https://twitter.com/Laintal
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Research papers
The Role of Ultraviolet Photons in Circumstellar Astrochemistry
https://arxiv.org/abs/2012.14715
In Situ Geochronology for the Next Decade
https://arxiv.org/abs/2101.01131
Possible Atmospheric Diversity of Low Mass Exoplanets
https://arxiv.org/abs/2101.01277
Searching for Small Circumbinary Planets
https://arxiv.org/abs/2101.03186
The Copernican Principle Rules Out BLC1 as a Technological Radio Signal from the Alpha Centauri System
https://arxiv.org/abs/2101.04118
Around which stars can TESS detect Earth-like planets
https://arxiv.org/abs/2101.07898
Probing the capability of future direct imaging missions to spectrally constrain the frequency of Earth-like planets
https://arxiv.org/abs/2101.07378
Vertically resolved magma ocean-protoatmosphere evolution
https://arxiv.org/abs/2101.10991
Constraints on Planets in Nearby Young Moving Groups Detectable by High-Contrast Imaging and Gaia Astrometry
https://arxiv.org/abs/2101.11130
Complications in the ALMA Detection of Phosphine at Venus
https://arxiv.org/abs/2101.09831
Claimed detection of PH3 in the clouds of Venus is consistent with mesospheric SO2
https://arxiv.org/abs/2101.09837
The Extended Habitable Epoch of the Universe for Liquids Other than Water
https://arxiv.org/abs/2101.10341
Refining the transit timing and photometric analysis of TRAPPIST-1
https://arxiv.org/abs/2010.01074
Characterisation of the hydrospheres of TRAPPIST-1 planets
https://arxiv.org/abs/2101.08172
Super-Earths M Dwarfs and Photosynthetic Organisms Habitability in the Lab
https://arxiv.org/abs/2101.04448
Persistence of Flare-Driven Atmospheric Chemistry on Rocky Habitable Zone Worlds
https://arxiv.org/abs/2101.04507
Characterizing Atmospheres of Transiting Earth-like Exoplanets Orbiting M Dwarfs with James Webb Space Telescope
https://arxiv.org/abs/2101.04139
Oceanic Superrotation on Tidally Locked Planets
https://arxiv.org/abs/2101.11784
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Interesting News items
FORTHCOMING STAR PARTIES -
STARDATE – SOUTH ISLAND. Waitangi weekend, Fri 5th -Mon 8th February 2021. Staveley. Keep an eye on https://cas.org.nz/
STARDATE. Fri 12 and Sat 13 February 2021, at Stonehenge. Phoenix Astronomical Society. Contact secretary@astronomynz.org.nz
The Stars are Comforting
https://www.rnz.co.nz/concert/programmes/stars
Spectroscopy Can Offer New Details of Surface of Venus
http://spaceref.com/venus/six-wavelength-spectroscopy-can-offer-new-details-of-surface-of-venus.html
Some sensible points in here
https://undark.org/2021/01/18/astronomy-discoveries-fall-victim-to-hype/
Astronomers estimate Titan's largest sea is 1,000-feet deep
https://www.eurekalert.org/pub_releases/2021-01/cu-aet012021.php
Starlink Satellites Are Fainter Now — But Still Visible
https://skyandtelescope.org/astronomy-news/starlink-satellites-fainter-but-still-visible/
Beyond Starlink: The Satellite Saga Continues
https://skyandtelescope.org/astronomy-news/beyond-starlink-the-satellite-saga-continues/
CHEOPS finds unique planetary system
http://nccr-planets.ch/blog/2021/01/25/cheops-finds-unique-planetary-system/
http://spaceref.com/exoplanets/cheops-finds-a-unique-planetary-system.html
6 Things to Know About NASA’s Mars Helicopter on Its Way to Mars
https://www.jpl.nasa.gov/news/6-things-to-know-about-nasas-mars-helicopter-on-its-way-to-mars
Saturns Tilt
http://spaceref.com/saturn/saturns-tilt-is-caused-by-its-moons.html
The 7 Rocky TRAPPIST-1 Planets May Be Made of Similar Stuff
https://www.jpl.nasa.gov/news/the-7-rocky-trappist-1-planets-may-be-made-of-similar-stuff
TRAPPIST-1's 7 Rocky Planets May Be Made of Similar Stuff
https://www.unibe.ch/news/media_news/media_relations_e/media_releases/2021/media_releases_2021/trappist_1_s_7_rocky_planets_may_be_made_of_similar_stuff/index_eng.html
TRAPPIST-1: Seven Worlds of Similar Compostion
https://www.centauri-dreams.org/2021/01/26/trappist-1-seven-worlds-of-similar-compostion/
Mercury
http://spaceref.com/mercury/study-reveals-messenger-watched-a-meteoroid-strike-mercury.html
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Updates from Andrew B,
Mars Science Laboratory Curiosity.
Sol 2,989. Saturday 2nd January 2021.
LMST = Local Mars Standard Time in Gale Crater.
Some stunning Navigation Camera, Hazard Camera and a MAHLI (MArs Hand Lens Imager) shots looking around from a vantage. point at the newly named “Sands of Forvie”.
The MAHLI colour image shows a tiny portion of one dune.
The wheel tracks are 40 CM wide and are 2.8 metres apart.
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 temperature here was minus 4 Celsius / 25 Fahrenheit (very warm indeed for Mars) with a sunrise low of minus 85 Celsius / minus 121 Fahrenheit.
Atmospheric pressure was 8.34 mb. Winds light, sunny by day, clear at night, with some elevated dust, but reducing hence the wider range of temperature on this sol.
The Sun as seen from Mars was in front of the constellation of Scorpius the Scorpion, the Earth was in front of the constellation of Virgo the Virgin, not long after coming out of inferior conjunction from in front of the Sun on: Tuesday 13th October 2020. The Earth is bright at magnitude minus 1.96 as a very bright morning star on Mars.
Jupiter & Saturn were only about 2.5 degrees apart in front of the constellation of Sagittarius the Archer and on: Monday 1st February 2021, Jupiter and Saturn will undergo a very close conjunction as seen from Mars, about 10 arc minutes apart. Very much like the one as seen from Earth on: Monday 21st December 2020.
HazCams / Hazard Cameras, NavCams / Navigation Cameras & MAHLI / MArs Hand Lens Imager.
Text: Andrew R Brown.
NASA / JPL / Malin Space Science Systems. Mars Science Laboratory Curiosity.
Jupiter.
Imaged: Wednesday 30th December 2020.
The Great Red Spot seen from the west during the Perijove 31 JUNO Spacecraft pass. I have cropped, enhanced and slightly enlarged this from the original.
There is also a large area of gigantic towering, thunderstorms to the upper left or north west of the Great Red Spot, seen as a brilliant white patch of clouds. These are certainly a mixture of water ice and ammonia ice crystals at the tops of gigantic cumulonimbus clouds at Jupiter's tropopause (the boundary between the troposphere and stratosphere of Jupiter), rising at least 65 KM / 40 miles above their bases, deeper in Jupiter's troposphere.
Perijove is the closest point to Jupiter in a Jovecentric (Jupiter centred) orbit.
JUNO passed about 4,200 KM / 2,608 miles above Jupiter's stormy cloud tops at a speed of 216,606 KPH / 134,000 MPH or 60.17 Kilometres / 37.38 miles per second, (from the Earth to the Moon in less than two hours).
The Great Red Spot is a high pressure, anticyclonic storm in Jupiter's southern hemisphere. The wind speeds at the centre are more or less zero, but around the edge, blow at about 530 KPH / 330 MPH. The centre of the Great Red Spot is about 8 KM / 5 miles higher than the edges. The depth of the Great Red Spot is at least 400 KM / 250 miles & possibly very much deeper than that, maybe at least 1,000 KM / 621 miles deep according to some recent research.
The Great Red Spot is shrinking. In January 1800, it was about 40,000 KM / 25,000 miles long, or about three times wider than the Earth.
Forward 204 years to January 2004, it has shrunk to only about half the length to 20,000 KM / 12,500 miles long and by April 2007 had shrunk further to 16,350 KM / 10,160 miles long.
By January 2040, the Great Red Spot may be circular, rather than oval, and by January 2150, may be gone completely (will not be around then).
Jupiter orbits the Sun once every 11.86 years or 11 years & 315 days at an average distance of 778.57 million KM / 483.78 million miles from the Sun. Jupiter rotates on it's axis once every 9 hours & 56 minutes, the shortest day of any of the planets in our solar system.
Jupiter is the largest planet in our solar system, 142,984 KM / 88,846 miles wide through the equator (11.21 times wider than the Earth) and 133,692 KM / 83,082 miles through the poles (10.25 times wider than the Earth).
Jupiter is also the most massive planet in our solar system with a mass of 317.8 times that of the Earth or about 1.898.2 trillion trillion tons (1,898.2 followed by twenty two zeros) and a mean global density of 1.326 g/cm3 (grams per cubic centimetre). Jupiter's rapid rotation causes the equator to bulge out and the polar regions to flatten, hence the somewhat oval shape of Jupiter.
Our own Earth with a diameter of 12,742 KM / 7,917 miles, with a mass of 5,972.2 billion trillion tons (5,972.2 followed by twenty zeros) and a mean global density of 5.517 g/cm3.
Jupiter is a gas giant, mostly composed of compressed hydrogen and helium, with new evidence pointing at a dense core of rock and metal roughly 15 times the mass of the Earth at the centre. About the inner two thirds of Jupiter appears to be composed of Metallic Hydrogen, liquid hydrogen under so much pressure, that the regular diatomic hydrogen H2 (two atoms consisting on one Proton with one electron each) are squashed together so hard that the compressed hydrogen acts as liquid metal as is conductive.
Within Jupiter to put it simply, this huge layer of metallic hydrogen is convecting and is generating Jupiter's gigantic magnetosphere, with traps particles from the Sun creating belts of very powerful radiation.
Jupiter's atmosphere is about 89% Hydrogen (including a very small amount of Deuterium / Heavy Hydrogen which is one proton and one neutron in the atomic nucleus and one electron), 11% Helium and a tiny fraction of 1% contains methane, water vapour, ammonia, carbon dioxide and carbon monoxide.
Two of Jupiter's large Galilean moons, Io and Europa orbit within one of these, hence radiation hardened spacecraft are needed to approach these two fascinating and very different moons.
Both Io and Europa have been successfully approached by Voyager 1, Voyager 2 and Galileo, these were radiation hardened as the earlier Pioneer 10 way back on Monday 3rd December 1973 was nearly fried by the trapped radiation near Io. It was by sheer luck Pioneer 10 survived but this finding meant all future spacecraft closely approaching Jupiter and the inner moons would be radiation hardened including the current JUNO spacecraft. Ganymede (Jupiter's and the Solar System's largest and most massive moon) is sometimes inside and at times outside of intense radiation and only the very large Callisto (Jupiter's second largest and the Solar System's third largest moon) out of the very large moons orbits permanently outside of dangerous radiation. All of the four smaller inner moons (Thebe, Amalthea, Adrastea and Metis from outside in) are all within intense trapped radiation. Jupiter's vastly extended family of outer moons (most of which are very small) are all outside of the radiation belts.
Crop and enhancement of image & text: Andrew R Brown.
JunoCam.
NASA / JPL-Caltech / SWRI / Malin Space Science Systems. JUNO spacecraft.
Good Afternoon (here anyway) everyone.
Fantastic footage seen here from the Heliospheric Imager (SoloHI) camera on board the ESA / NASA Solar Orbiter. SoloHi is used for imaging the space environment around the spacecraft as is a very low light level camera.
On: Wednesday 18th November 2020, Venus (left, amazingly bright and fairly close at about 48 million KM / 29.825 million miles from Solar Orbiter) Earth and Mars (bottom right near the corner, the Earth, very much the brighter of the pair). The Second, Third and Fourth Rocks from the Sun appear to move beneath the main part of the constellation of Aries the Ram with passes through the central part of the frame.
I hope we get to see more footage like this, three very familiar objects seen from a very alien perspective.
I have attached two stills, one I labled and one unlabled.
Andrew.
https://www.esa.int/ESA_Multimedia/Videos/2021/01/Solar_Orbiter_snaps_V
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RASNZ
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. Royal Astronomical Society of New Zealand
. Email Newsletter Number 241, 20 January 2021
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Affiliated Societies are welcome to reproduce any item in this email
newsletter or on the RASNZ website http://www.rasnz.org.nz/
in their own newsletters provided an acknowledgement of the source is
also included.
Contents
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1. Rocky Planet Found Orbiting an Ancient Star
2. Reminders for Members
3. The Solar System in February
4. Star Parties
5. Stardate South Island - Waitangi Weekend 2021 - Staveley
6. Variable Stars News
7. Young Black Hole Overweight
8. Missing Pleiad Explained?
9. Removing Space Junk
10. How to Join the RASNZ
11. Gifford-Eiby Lecture Fund
12. Quotes
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1. Rocky Planet Found Orbiting an Ancient Star
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Astronomers have found an Earth-size (but not at all Earth-like) planet around an ancient star that has a nice high view of our galaxy.
Astronomers have discovered three planets orbiting a star about 10 billion years old — one of them rocky. The star, TOI 561 (meaning it was the 561st object of interest from the Transiting Exoplanet Survey Satellite), is in our galaxy’s older thick disk, which means its planets have a nice view from on high of the Milky Way’s spiral.
The star has three planets, with diameters 1.5, 3, and 2 times Earth’s. The innermost one is rocky, with three times Earth’s mass, but on a period of 0.44 days, it’s anything but Earth-like. Its dayside surface temperature is around 2500K (2,200 C). That’s almost twice as hot as Earth’s magma, and it’s surely molten. What it actually looks like is uncertain, because as lead scientist Lauren Weiss (University of Hawaii, Manoa) notes, “It exceed temperatures where geophysicists have made lava in the lab.”
Astronomers have found planets around old stars before, and even around chemically poor stars that have a paucity of heavy elements. Yet the mere fact that this planet came to be is of interest to astronomers. “We now have evidence that the universe has been forming rocky planets for the last 10 billion years, more than double the age of our own solar system, and nearly since the origin of the universe itself,” Weiss says.
-- See Monica Young's article with graphics at https://skyandtelescope.org/astronomy-news/rocky-planet-found-around-10-billion-year-old-star/
The original paper is at https://arxiv.org/abs/2009.03071
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2. Reminders for Members
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2021 RASNZ Conference in Wellington
The 2021 RASNZ conference is planned to be held in Wellington from Friday 9th until Sunday 11th July 2021. Come along for this special 100th anniversary conference! A Dark Skies workshop is also planned. Keep an eye on the RASNZ webpage for details as they evolve, https://www.rasnz.org.nz/ .
RASNZ 2021 Subscriptions Due
The 2021 RASNZ subscriptions are due on the 1st of January 2021. See - https://www.rasnz.org.nz/rasnz/payments-and-donations .
For bank transfer payments the details are
ASB Bank - Riccarton Branch
Account name RASNZ
Account number 12-3147-0384735-00
If the payment covers more than membership then please note that.
Subscription rates were not correctly shown on the payments page of the
RASNZ Website following the non-publication of Astronomy Year Book for
2021. This has meant some people will have overpaid if they ordered a
copy with their subscription. If so please email: treasurer@rasnz.org.nz
with details of the payment and your bank details.
RASNZ Section and Group Reports for 2020 are due in Early March –
Could the RASNZ Section and Group leaders please send their 2020 report to the Executive Secretary (kiwiastronomer@gmail.com) at least two months before the AGM, thus, by 10th March 2021. Note, thanks to COVID-19, the 2021 AGM date is yet to be determined. It may be a Zoom AGM in May (to meet the Charities Commission requirements) or it may be physically held at the actual July 2021 conference in Wellington. We will know more soon, however, it is best to set the deadline for the 10th March 2021.
These reports will be published in Southern Stars. RASNZ By-Law F14 states, 'Each year, not less than eight weeks before the date of the Annual General Meeting, each Section shall provide Council with a report of its activities during the previous calendar year and where the section holds a bank account in the Society’s name, a financial statement.'
Southern Stars
Got an interesting astronomical story, area of astronomical research or article to share? Southern Stars editor Bob Evans would love to hear from you! He’s always keen to see more articles in Southern Stars. Southern Stars is the journal of the RASNZ and an excellent forum to publish within. Write to bevans@xtra.co.nz
-- Mostly from Keeping in Touch #41, 28th December 2020.
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3. The Solar System in February
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Dates and times shown are NZDT (UT + 13 hours). Rise and Set times are for Wellington. They will vary by a few minutes elsewhere in NZ. Data is adapted from that shown by GUIDE 9.1.
THE SUN and PLANETS in FEBRUARY, Rise & Set Magnitude & Constellation
Feb 1 NZDT Feb 28 NZDT
Mag Cons Rise Set Mag Cons Rise Set
SUN -26.7 Cap 6.24am 8.43pm -26.7 Aqr 6.58am 8.07pm
Merc 1.3 Cap 7.43am 9.08pm 0.2 Cap 4.46am 6.54pm
Venus -3.9 Cap 5.18am 8.06pm -3.9 Aqr 6.22am 7.57pm
Mars 0.5 Ari 2.09pm 12.16am 0.9 Tau 1.41pm 11.14pm
Jup -2.0 Cap 6.13am 8.37pm -2.0 Cap 4.57am 7.06pm
Sat 0.6 Cap 5.49am 8.22pm 0.7 Cap 4.15am 6.42pm
Uran 5.8 Ari 1.36pm 12.09am 5.8 Ari 11.53am 10.24pm
Nep 7.9 Aqr 9.34am 10.19pm 8.0 Aqr 7.52am 8.35pm
Pluto 14.6 Sgr 4.51am 7.50pm 14.6 Sgr 3.09am 6.07pm
February 1 NZDT February 28 NZDT
Twilights morning evening morning evening
Civil: start 5.56am, end 9.12pm start 6.32am, end 8.34pm
Nautical: start 5.18am, end 9.50pm start 5.58am, end 9.08pm
Astro: start 4.36am, end10.32pm start 5.23am, end 9.43pm
FEB PHASES OF THE MOON, times NZDT & UT
Last quarter: Feb 5 at 6.37am (Feb 4, 17:37 UT)
New Moon: Feb 12 at 8.06am (Eeb 11, 19:06 UT)
First quarter: Feb 20 at 7.47am (Feb 19, 18:47 UT)
Full Moon: Feb 27 at 9.17pm (Feb 27 08:17 UT)
THE PLANETS in FEBRUARY
MERCURY will slip out of the evening sky, probably unnoticed, during the first week of February. The planet is at inferior conjunction, between Earth and Sun on the 8th (very early 9th for NZ). At their closest Mercury would appear nearly 4° from the Sun. Mercury's magnitude will then be 5.2.
By the end of February Mercury should be visible in the morning sky: an hour before sunrise it will be 12° up, a little to the south of east. Jupiter will be 3° to the lower right of Mercury and should help in locating the innermost planet. But this will be about 6 am close to the start of Nautical twilight with the Sun 12° below the horizon.
MARS is the only naked eye planet visible in the evening sky throughout February. It moves from Aries to Taurus on the 24th and ends the month less than 4° from the Matariki (Pleiades) star cluster. At 10 pm Mars will be to the northwest about 11° above the horizon
VENUS is a morning sky object during February, rising over an hour before the Sun on the 1st and some 30 minutes before the Sun on the 28th. Both in morning twilight. It will be very low rather to the south of east.
The planet starts February as the furthest from the Sun of the four morning objects; by the end of the month it will be the nearest to the Sun. It passes Saturn, Jupiter and Mercury during the month.
On the morning of February 12 about 30 minutes before sunrise, the crescent moon will be just over 1° from Venus, the latter being a little under 8° above the horizon.
JUPITER and SATURN having been in conjunction with the Sun towards the end of January, are morning objects in February with Saturn the higher. The two planets are 8° apart at the end of the month
Venus is at conjunction with the two outer planets during the month, Saturn is at its closest to Venus on the morning of February 7 when they will be just over half a degree apart with Saturn to the upper left of Venus as seen, when visible, in NZ. Jupiter's conjunction with Venus is 5 mornings later with the two just under half a degree apart as seen from NZ.
Both conjunctions take place during morning twilight with the planets very low, a little to the south of east, making observation difficult. Venus should be visible by eye, Saturn may need the assistance of binoculars.
PLUTO, like Saturn and Jupiter is a morning object rising about an hour before Saturn.
URANUS is in the evening sky. It sets shortly after midnight on February 1 and about 10.30 pm on the 28th.
NEPTUNE is also an evening object but will set before the end of astronomical twilight on the 1st and before the end of civil twilight by the 28th.
POSSIBLE BINOCULAR ASTEROIDS in February
FEB 1 NZDT FEB 28 NZDT
Mag Cons transit Mag Cons transit
(1) Ceres 9.3 Aqr 4.21pm 9.2 Psc 3.11pm
(4) Vesta 6.7 Leo 4.13am 6.1 Leo 2.20am
(14) Irene 9.2 Cnc 1.05am 9.8 Cnc 10.58pm
(15) Eunomia 8.8 Cnc 12.36am 9.5 Gem 10.32pm
(18) Melpomene 9.4 Cnc 1.32am 10.2 Cnc 11.23pm
(29) Amphitrite 9.6 Leo 3.20am 9.2 Leo 1.09am
CERES is an evening object, setting at 11pm on the 1st and just after 9.30 pm on the 28th. Thus it is getting low in the evening sky.
VESTA is mainly a morning object, rising just before 11pm on the 1st and just after 9.30 pm on the 28th. On the morning of the 27th the almost full moon will be just under 6° to the left of Vesta
IRENE and EUNOMIA start February in Cancer. Following their January oppositions, they both fade during the month.
MELPOMENE is at opposition on February 1 at magnitude 9.4. It fades nearly a magnitude during the month.
AMPHITRITE, in Leo, is at opposition on February 23 at magnitude 9.1. At the end of February it will be less than 4° from Regulus.
-- Brian Loader
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4. Star Parties
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Stardate - South Island. Waitangi weekend, Fri 5th-Mon 8th February 2021. Staveley. See next item for details.
Stardate. Fri 12th and Sat 13th February 2021, at Stonehenge. Phoenix Astronomical Society. Contact secretary@astronomynz.org.nz
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5. Stardate South Island - Waitangi Weekend 2021 - Staveley
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Stardate SI will be held at Staveley Camp 5-8 Feb and will add an extra night this year due to the long weekend. This is an awesome event and one that's great for the kids as there's plenty of space outside for them too. All the normal activities: lectures, pot luck dinner, telescope walk, solar viewing, kid's activities etc. plus some great observing from a dark sky location. Plenty of space to camp and great facilities makes it fun weekend for the family.
Bookings information can be found at Euan's website:
http://www.treesandstars.com/stardate/
Detailed information will be available soon and we will send out an agenda including the booking site link and prices in our email updates.
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6. Variable Star News
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AAVSO (American Association of Variable Star Observers) is hosting another year long series of webinars for free in 2021. See the AAVSO website for upcoming events. There are also AAVSO “How to Hours”. The first two are: February 6 (19:00 UT) Introduction to VS and how to observe them; March 6 (19:00 UT) How to do DSLR photometry.
AAVSO also offer CHOICE educational courses. The initial two are: Feb 1-26, Fundamental Statistics for Photometry; March 1–26, Variable Star Classification and Light Curves. There is a charge for CHOICE courses.
This information is from the AAVSO Community Communication Jan 2021. To see the information, and for links for further information and to register, use https://mailchi.mp/aavso/aavso-communications-january-2021?e=e75acde184
For information on Variable Stars South observing projects visit the VSS website, read the information and if interested contact the project leader. There is a link to the project descriptions here: https://www.variablestarssouth.org/projects/
-- Alan Baldwin
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7. Young Black Hole Overweight
------------------------------
Quasars are the lighthouses of the sky, magnificent structures that surround supermassive black holes in distant galaxies. These celestial lighthouses must take time to build, so they shouldn’t just appear overnight. That’s why young quasars present such a conundrum. Somehow, these active galaxies manage to assemble a black hole with the mass of more than a billion Suns early on in the universe.
Now, Feige Wang (University of Arizona) and colleagues have detected a record-breaking quasar: a 1.6 billion solar-mass black hole just 670 million years after the Big Bang (or a redshift of 7.64) — around the era when the first stars began to shine. The result, which uses data collected by the Magellan Telescope in Chile before the pandemic began, appears in the Astrophysical Journal Letters Read the preprint online at https://arxiv.org/abs/2101.03179 .
The three most distant quasars have been discovered in the last three years, and this one, dubbed J0313–1806, is only about 20 million light-years farther away than the previous record holder. But it’s twice as massive and as such, it’s making astronomers wonder just how these massive objects come to be built so quickly.
Astronomers have found themselves in two schools of thought regarding supermassive black hole formation. One school posits that black holes come from stars, albeit very massive ones or ones in special conditions. For example, the very first generation of stars, known as Population III stars, likely were far more massive than later generations, on the order of hundreds of solar masses. They burned fast and died young, and therefore could have been the seeds of supermassive black holes. Dense star clusters might have accelerated their growth.
The other school of thought skips stars entirely and goes for the direct collapse of cold clouds of gas, something not possible now but thought to be possible in the crowded early universe.
The record-breaking quasar may help decide the issue. Even if this black hole were gaining mass at the maximum rate, 100% of the time, Wang and colleagues find that it would still need to have been huge — as in, 10,000 times the Sun’s mass [per year?] — to weigh in at 1.6 billion Suns by the time it’s observed. Wang’s team thus rules out a massive star or star cluster for the formation of this black hole.
“This tells you that no matter what you do, the seed of this black hole must have formed by a different mechanism,” says team member Xiaohui Fan (also at University of Arizona), who presented the find at the 237th meeting of the American Astronomical Society. “In this case, one that involves vast quantities of primordial, cold hydrogen gas directly collapsing into a seed black hole.”
“I think these large masses at redshifts greater 7 put a huge amount of pressure on models that assume Population III seeds,” agrees Mitch Begelman (University of Colorado), who was not involved in the research. “Even with direct collapse to a 10,000-solar-mass seed,” he adds, “the seed would have to grow at [the maximum] rate for the entire time.” But Begelman doesn’t rule out growth above the so-called maximum.
The maximum growth rate comes from the fact that black holes eat like the Cookie Monster —and there’s a point at which more crumbs go out than in. But Begelman and other theorists have established that, under the right conditions, black holes can actually feed at more than the maximum level. That means they don’t have to be at the maximum level all the time — they might feed at extreme rates, but intermittently.
“The problem is,” Fan points out, “so far all the quasars we’ve observed, at the times they were observed, they were obeying [that] limit.” J0313–1806, for example, is growing at just about the maximum level, ingesting 25 Suns’ worth of mass each year. Maybe at even earlier times black holes fed at more extreme rates.
The only way to find out is to go back even further. But as Begelman points out, they'll need to look carefully. “Black holes that are hyper-accreting might not look like quasars,” he says, noting that dense dust might surround these objects. “We might not be looking for them the right way!”
Besides powering the most distant quasar known, the black hole at the centre of J0313–1806 is also powering a gale of hot gas that’s traveling outward and into the galaxy at 20% of the speed of light. Such outflows might be common in the early universe, when both galaxies and their black holes were growing at tremendous rates.
But what such winds do to their galaxies’ evolution is still a matter of debate. Observations with the Atacama Large Millimeter/submillimeter Array in Chile show the galaxy that hosts the quasar is forming stars at a rate of 200 solar masses per year. With a wind of hot gas gusting through the galaxy, that churn may grind to a halt. Then all that will be left is a massive “dead” galaxy, where new stars are a rarity, with a behemoth black hole at the centre. (That is, unless another galaxy happens along to liven things up.)
-- See the original article by Monica Young, with graphics, at
https://skyandtelescope.org/astronomy-news/most-distant-quasar-supermassive-black-hole-birth/
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8. Missing Pleiad Explained?
----------------------------
Many cultures around the world refer to the Pleiades as “seven sisters” and also tell quite similar stories about them. Look carefully and you will probably count six stars. So why do we say there are seven of them?
After studying the motion of the stars very closely Ray Norris, a professor at the School of Science, Western Sydney University,
believes these stories may date back 100,000 years to a time when the constellation looked quite different.
In Greek mythology, the Pleiades were the seven daughters of the Titan Atlas. He was forced to hold up the sky for eternity, and was therefore unable to protect his daughters. To save the sisters from being raped by the hunter Orion, Zeus transformed them into stars. But the story says one sister fell in love with a mortal and went into hiding, which is why we only see six stars.
A similar story is found among Aboriginal groups across Australia. In many Australian Aboriginal cultures, the Pleiades are a group of young girls, and are often associated with sacred women’s ceremonies and stories. Close to the Seven Sisters in the sky is the constellation of Orion, which is often called “the saucepan” or "the pot" in the southern hemisphere. In Greek mythology Orion is a hunter. This constellation is also often a hunter in Aboriginal cultures, or a group of lusty young men.
The writer and anthropologist Daisy Bates reported people in central Australia regarded Orion as a “hunter of women”, and specifically of the women in the Pleiades. Many Aboriginal stories say the boys, or man, in Orion are chasing the seven sisters – and one of the sisters has died, or is hiding, or is too young, or has been abducted, so again only six are visible.
Similar “lost Pleiad” stories are found in European, African, Asian, Indonesian, Native American and Aboriginal Australian cultures. Many cultures regard the cluster as having seven stars, but acknowledge only six are normally visible, and then have a story to explain why the seventh is invisible.
How come the Australian Aboriginal stories are so similar to the Greek ones? Anthropologists used to think Europeans might have brought the Greek story to Australia, where it was adapted by Aboriginal people for their own purposes. But the Aboriginal stories seem to be much, much older than European contact. And there was little contact between most Australian Aboriginal cultures and the rest of the world for at least 50,000 years. So why do they share the same stories?
Barnaby Norris and Ray Norris suggest that the seven sisters story goes back 100,000 years before humans began moving out of Africa. The story was carried with them as they travelled to Australia, Europe, Asia and Polynesia.
Careful measurements with the Gaia space telescope and others show the stars of the Pleiades are slowly moving in the sky. One star, Pleione, is now so close to the star Atlas they look like a single star to the naked eye. But if we take what we know about the movement of the stars and rewind 100,000 years, Pleione was further from Atlas and would have been easily visible to the naked eye. So 100,000 years ago, most people really would have seen seven stars in the cluster.
The authors believe this movement of the stars can help to explain two puzzles: the similarity of Greek and Aboriginal stories about these stars, and the fact so many cultures call the cluster “seven sisters” even though we see only six stars today. Their suggestion is set out in a paper to be published by Springer early next year in a book titled Advancing Cultural Astronomy, a preprint for which is available at https://www.dropbox.com/s/np0n4v72bdl37gr/sevensisters.pdf?dl=0 .
-- See Ray Norris's original article with charts at
https://theconversation.com/the-worlds-oldest-story-astronomers-say-global-myths-about-seven-sisters-stars-may-reach-back-100-000-years-151568
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9. Removing Space Junk
----------------------
Human beings are messy. They tend to leave rubbish behind them wherever they go—and to expect someone else to clear that rubbish up. This is true even in outer space. The problem of orbiting debris, and the concomitant risk of it colliding with and damaging an active and probably expensive satellite, has been around for a while. But it is rapidly getting worse. In the past three years, the number of times such bits of junk have almost hit operating satellites has roughly doubled.
That, at least, is the calculation made by Daniel Oltrogge, an expert whose conclusion is drawn from his two jobs. Mr Oltrogge is an adviser to the Space Data Association, an industry body that feeds orbital and manoeuvring information from many satellite operators into a computer model which forecasts likely collisions so that spacecraft, or at least those with appropriate thrusters, can be moved out of harm’s way. Mr Oltrogge is also the director of the centre for space standards and innovation at AGI, an American firm that develops orbital-mechanics software which also helps satellite operators sidestep collisions.
Part of the problem is the growing number of launches taking place. On January 13th, for example, Virgin Orbit, a firm in Richard Branson’s Virgin Group that is another new entrant to the market, launched ten satellites into orbit using a rocket released from a modified Boeing 747-400. Another part, though, is that, every year, a dozen or so sizeable chunks of debris orbiting Earth break up. Around half of these explosions are caused by things like the ignition of leftover rocket fuel and the bursting of old batteries and pressurised tanks. The rest are the result of collisions.
The upshot is a chain-reaction of impacts in orbit. Unlike the fictional version of such a chain-reaction, which inconvenienced Sandra Bullock’s character in “Gravity”, a film released in 2013, this real one is accelerating only slowly, so there is still time to curtail it. But if action is not taken soon, insurance premiums for satellites will rise, spending on tracking and collision-avoidance systems will have to increase, and certain orbits risk becoming unusable. If things get really bad, the authorities may even have to step in to restrict the number of launches.
Stopping this orbital-junk-generating chain reaction means casting part of the superfluous tonnage in space down into Earth’s atmosphere, where the frictional heat of re-entry will burn it up. A clean sweep is not necessary. Removing a handful of the larger derelicts every year would be enough. Exactly how many is debated. Yamamoto Toru of Japan’s space agency, JAXA, estimates somewhere between three and seven. Ted Muelhaupt of America’s Aerospace Corporation, a taxpayer-funded research centre, reckons a dozen. But even that sounds doable. Except that no one knows how to do it.
People are, though, planning to practice. One practice mission, scheduled for lift-off in March, is led by Astroscale, a firm based in Tokyo. Astroscale proposes to launch, from Baikonur Cosmodrome in Kazakhstan, a mission dubbed ELSA-d. This consists of a 175kg mother ship called a servicer, and a 17kg pod fitted with a ferrous docking plate that will act as a dummy target. If all goes well, the servicer will eject and recover the pod three times, in successively harder trial runs, before thrusters push the whole kaboodle to fiery doom in the atmosphere below.
In the first test, the servicer will use springs to push the pod out and then, once it is ten metres away, will approach it again, lock onto the docking plate using an arm fitted with a magnetic head, retract the arm and pull it back to the servicer. For the second test, it will push the pod at least 100 metres away before its starts approaching it. A reaction wheel and a set of magnetic torque-generators will then put the pod into a tumble involving all three axes of motion, at a speed of half a degree a second.
This is, as it were, an important twist—for chunks of orbiting debris typically spin in this fashion. A real deorbiting mission will therefore have to deal with such spinning objects. Markings on the pod will help the servicer work out its prey’s motion. Using eight thrusters, it will manoeuvre itself until those markings appear, to its sensors, to be stationary. This will mean its motion exactly matches that of the tumbling pod, and that the magnetic head can therefore be extended to do its job.
For the third capture test, the servicer will first use its thrusters to back off several kilometres from the pod, putting the pod beyond sensor range. Then it will search for it, as would need to be the case if it were hunting for a real derelict spacecraft.
For all the technological prowess these tests will require, however, real derelicts pose a greater challenge than dummy ones. For one thing, unlike Astroscale’s pod, few spacecraft have been designed to expedite their own removal. Also, those objects which most need removing are dangerously heavy. A spacecraft that miscalculates while attempting to capture such a piece of tumbling debris could be smashed to smithereens, thus contributing to the problem it was supposed to be solving.
The Commercial Removal of Debris Demonstration, a plan by JAXA to deorbit a discarded Japanese rocket stage, highlights these difficulties. Before a spacecraft can be designed to capture whichever derelict Japan’s space agency selects as the experiment’s target, a reconnaissance mission must first be launched to study it up close. JAXA has awarded the contract for this part of the demonstration to Astroscale, which plans to do it using a craft called ADRAS-J, which will be launched in two years’ time. To measure the motion and features of a rocket part that might weigh tonnes, ADRAS-J will approach within mere metres. Once it collects the necessary data, another spacecraft can be designed to seize the junk on a subsequent mission.
In this case, magnets will be not be used to grapple with the target, for normal spacecraft have no iron in them. Using a harpoon to capture such an object might, however, be feasible. In a test conducted in 2019, Airbus, a European aerospace giant, successfully shot a harpoon from a satellite into a piece of panelling 1½ metres away. That panelling was, however, attached to a boom extending from the satellite, so this was but the most preliminary of experiments. Also, a harpoon can miss, ricochet or—worse—break off parts of the target which will then contribute yet further objects to the celestial junkyard.
Another option is to shoot a net. Airbus tested this idea in 2018. That test successfully enveloped a small “cubesat” which had been pushed seven metres away from the net-throwing craft—though this net was not tethered to the mother ship, which would therefore have been unable to deorbit its target. Tethers, indeed, are hard to manage in the weightlessness of orbit, which is why Airbus chose not to use one in this preliminary net-tossing experiment. And some doubt that such cosmic retiarii are a sensible idea. Chris Blackerby, Astroscale’s chief operations officer, expects the best approach will be to design robotic arms to clench the target vehicle’s fairing ring (the shallow cylinder that connected it to the jettisoned launching stage that lifted it from Earth), if this is still intact.
If all that works, JAXA’s debris-removal demonstration will face a final challenge. This is to execute a safe re-entry. Many pieces of the re-entering complex of captor and captive will survive frictional melting and slam, at speed, into Earth’s surface. Were re-entry to occur at a random spot, the probability of a human casualty would now exceed the threshold of one in 10,000 that NASA, America’s space agency, set as an acceptable level of risk in 1995, and which was adopted by Japan and other countries thereafter. The complex will therefore need to be put into a steep descent aimed at an uninhabited area—probably part of the Pacific Ocean.
As to the first clearance of actual orbiting debris, that is likely to be a European affair, for, in 2019, the European Space Agency awarded a contract to ClearSpace, a Swiss firm, to grab a 100kg piece of rocket debris that has been looping Earth since 2013. This mission is scheduled for 2025.
ClearSpace plans to use a capture craft fitted with four robotic arms. Unlike harpoons or net tosses, this strategy permits repeated attempts at recovery to be made. Even so, Luc Piguet, ClearSpace’s boss, expects his spacecraft will spend at least nine months in trials near the target before it secures the derelict and decelerates sufficiently to descend.
An era of serious cleanup in space is still some way off. Besides the technological obstacles, removing junk will be expensive. In addition to the costs of lobbing something into orbit, controlled re-entry of an object requires fuel, big thrusters and close attention from a ground controller. These things can tack millions of dollars—perhaps more than $20m—onto a deorbiting operation’s price tag. ClearSpace’s mission, for example, may cost as much as €100m ($122m), though Mr Piguet hopes subsequent jobs will be cheaper.
Cheaper or not, though, the question remains, “who will pay”? The littering of space is a textbook example of the tragedy of the commons, in which it is in everyone’s interest for a problem to be solved, but no one’s to be the lone individual who takes on the burden of solving it.
The solutions to tragedies of the commons usually, therefore, have to be imposed from outside, often by governments. One idea is a special launch tax, with the proceeds hypothecated to pay for clean-up operations. A more creative proposal is what Mr Muelhaupt calls “a bottle-deposit system”. Spacefarers would pay a deposit for each craft they lofted into orbit. If owners then failed to deorbit their equipment after its mission was over, the job could be done by someone else, who would then collect the deposit. That would encourage people to build deorbiting capabilities into satellites from the start, so the celestial dustmen would eventually no longer be needed. A third suggestion, proposed by Akhil Rao of Middlebury College, in Vermont, is to charge rent, known as orbital-use fees, for every commercial satellite in orbit. That would have the same effect.
Support for such schemes is growing, though they would require both international agreements between countries with launch facilities and an enforcement mechanism to stop outsiders with laxer rules from undercutting the arrangement.
There is also one other point. As Jean-Daniel Testé, once head of the French air force’s joint space command, notes, equipment developed for orbital cleanup could also be used to disable satellites. Mr Testé says advances in orbital robotics made by France’s adversaries, not to mention the lack of any international “space gendarmerie”, are leading his country to plan spacecraft to defend its military and intelligence satellites.
Mr Testé is coy on specifics. But France’s armed-forces minister, Florence Parly, has revealed more about her country’s plans than have her equivalents in other powers, America included. She foresees France launching special “lookout” and “active defence” spacecraft, to protect its assets in space. The latter are likely to be armed with powerful lasers. As Ms Parly has put it, “we intend to blind” threatening spacecraft. Preferably without disintegrating them.
-- From The Economist, Science & technology, January 12th 2021.
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10. How to Join the RASNZ
--------------------------
RASNZ membership is open to all individuals with an interest in
astronomy in New Zealand. Information about the society and its
objects can be found at
http://rasnz.org.nz/rasnz/membership-benefits
A membership form can be either obtained from treasurer@rasnz.co.nz or
by completing the online application form found at
http://rasnz.org.nz/rasnz/membership-application
Basic membership for the 2021 year starts at $40 for an ordinary
member, which includes an electronic subscription to our journal
'Southern Stars'.
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11. Gifford-Eiby Lecture Fund
------------------------------
The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to
assist Affiliated Societies with travel costs of getting a lecturer
or instructor to their meetings. Details are in RASNZ By-Laws Section
H and at http://rasnz.org.nz/rasnz/ge-fund
The application form is at
http://rasnz.org.nz/Downloadable/RASNZ/GE_Application2019.pdf
================================================================
12. Quotes
----------
"Keep the company of those who seek the truth; run from those who have found it." -- Vaclav Havel. (Quoted in The Economist, 200815, Letters.)
"The aim of argument or of discussion, should not be victory, but progress." -- Joseph Joubert.
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Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
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December Celestial Calendar by Dave Mitsky
January Celestial Calendar by Dave Mitsky
All times are UT (subtract five hours, and one calendar day when appropriate, for EST)
1/2 The Earth is at perihelion (147,093,463 kilometers or 91,399,454 miles distant from the Sun) at 13:51
1/3 The peak of the Quadrantid meteor shower (40 to 120 or more per hour) is predicted to occur at 14:30; the Moon is 4.5 degrees north of the first-magnitude star Regulus (Alpha Leonis) at 2:00
1/4 The latest sunrise of the year at latitude 40 degrees north occurs today
1/5 Mercury is at its southernmost latitude from the ecliptic plane (-7.0 degrees) at 9:00
1/6 Last Quarter Moon occurs at 9:37
1/7 The latest onset of morning twilight of the year at latitude 40 degrees north occurs today; the Moon is 6.4 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 0:00; the Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to begin at 7:08
1/9 The Moon is at perigee, subtending 32’ 32" from a distance of 367,389 kilometers (228,284 miles), at 15:37
1/10 Mercury (magnitude -0.9) is 1.6 degrees southeast of Saturn (magnitude +0.6) at 5:00; the Moon is 5.4 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 6:00; Mercury, Jupiter, and Saturn lie within a circle with a diameter of 2.4 degrees at 19:00; the Moon is at the descending node (longitude 259.7 degrees) at 20:00
1/11 Mercury (magnitude -0.9) is 1.4 degrees southeast of Jupiter (magnitude -1.9) at 19:00; the Moon is 1.5 degrees south of Venus at 21:00
1/12 Venus is at its southernmost declination (-23.2 degrees) at 6:00
1/13 New Moon (lunation 1201) occurs at 12:13; the Moon is 3.2 degrees southeast of Saturn at 23:00
1/14 The Moon, Mercury and Saturn lie within a circle with a diameter of 6.0 degrees at 0:00; the Moon, Jupiter, and Saturn lie within a circle with a diameter of 3.8 degrees at 0:00; the Moon is 3.3 degrees southeast of Jupiter at 3:00; the Moon, Mercury and Jupiter lie within a circle with a diameter of 4.0 degrees at 5:00; Pluto is in conjunction with the Sun (35.18 astronomical units from the Earth, latitude -1.2 degrees) at 7:00; the Moon is 2.3 degrees southeast of Mercury at 10:00; Uranus is stationary, with prograde (eastward) motion to commence, at 11:00
1/16 Venus is at the descending node through the ecliptic plane at 12:00
1/17 The Moon is 4.1 degrees southeast of Neptune at 10:00
1/19 The Sun enters Capricornus (ecliptic longitude 299.7 degrees) at 15:00; the Sun's longitude is 300 degrees at 21:00
1/20 The Lunar X (the Purbach or Werner Cross), an X-shaped clair-obscure illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be fully formed at approximately at 18:31; Mars (magnitude +0.2) is 1.6 degrees north-northwest of Uranus (magnitude +5.8) at 20:00; First Quarter Moon occurs at 21:02
1/21 The Moon is 3.1 degrees southeast of Uranus at 10:00; the Moon, Mars, and Uranus lie within a circle with a diameter of 4.6 degrees at 10:00; the Moon is 4.7 degrees southeast of Mars at 11:00; the Moon is at apogee, subtending 29' 33" from a distance of 404,360 kilometers (251,258 miles), at 13:11; asteroid 15 Eunomia (magnitude +8.4) is at opposition in Cancer at 19:00
1/22 Mars is 1.7 degrees north of Uranus at 0:00
1/23 Asteroid 4 Vesta (magnitude +7.1) is stationary in Leo at 22:00; the Moon is 5.7 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 10:00
1/24 Mercury is at greatest eastern elongation (18.6 degrees) at 2:00; Saturn is in conjunction with the Sun at 3:00; the Moon is 4.0 degrees north of Aldebaran at 4:00; asteroid 14 Irene (magnitude +9.3) is at opposition in Cancer at 17:00; Mercury is at the ascending node through the plane of the ecliptic at 10:00; the Moon is at the descending node (longitude 79.1 degrees) at 22:00
1/26 The Moon is 0.3 degrees north-northeast of the bright open cluster M35 in Gemini at 0:00; Uranus is at eastern quadrature (90 degrees from the Sun) at 13:00
1/27 The Moon is 7.4 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 11:00; the Moon is 3.8 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 16:00
1/28 The Moon is 2.6 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 17:00; Full Moon (known as the Ice Moon, the Moon after Yule, the Old Moon, and the Wolf Moon) occurs at 19:16
1/29 Jupiter is in conjunction with the Sun (6.071 astronomical units from the Earth, latitude -0.63 degrees) at 2:00; Mercury is at perihelion (0.3075 astronomical units from the Sun) at 2:00
1/30 Mercury is stationary, with retrograde (western) motion to commence, at 2:00; the Moon is 4.4 degrees north-northeast of Regulus at 9:00
Johannes Hevelius (1611-1687), Ernst Abbe (1840-1905), George Van Biesbroeck (1880-1974), Luboš Kohoutek (1935), and Stephen Hawking (1942) were born this month.
Galileo Galilei discovered Io, Europa, and Callisto on January 7, 1610. Galileo Galilei discovered Ganymede on January 13, 1610. Nicolas-Louis de Lacaille discovered the emission nebula NGC 3372 (the Eta Carinae Nebula) on January 25, 1752. Charles Messier discovered the globular cluster M56 on January 23, 1779. Charles Messier discovered the globular cluster M80 on January 4, 1781. William Herschel discovered the spiral galaxy NGC 1084 on January 10, 1785. Pierre François André Méchain discovered Comet 2P/Encke on January 17, 1786. William Herschel discovered Titania and Oberon, two satellites of Uranus, on January 11, 1787. Giuseppe Piazzi discovered the first asteroid, 1 Ceres, on January 1, 1801. Louis Daguerre took the first photograph of the Moon on January 2, 1839. Alvan Clark discovered the white dwarf star Sirius B (the Pup) on January 31, 1862. The 36-inch Clark refractor at the Lick Observatory saw first light on January 3, 1888. Charles Perrine discovered the Jovian satellite Elara on January 2, 1905. Philibert Jacques Melotte discovered the Jovian satellite Pasiphae on January 27, 1908. Clyde Tombaugh photographed Pluto on January 23, 1930. Mike Brown, Chad Trujillo, and David Rabinowitz discovered Eris on January 5, 2005.
The Quadrantid meteor shower is predicted to peak around 9:30 a.m. EST (14:30 UT) on January 3rd. The radiant lies at the junction of the constellations of Boötes, Hercules, and Draco, in what was once called Quadrans Muralis, and is highest just prior to dawn. Unfortunately, an 84%-illuminated gibbous Moon will compromise the peak of this year’s Quadrantids. The Quadrantid shower can sometimes reach zenithal hourly rates of more than 100 meteors per hour for a relatively short period of time. The near-Earth asteroid 2003 EH1, which may be an extinct comet, is believed to be the source of these meteors. See https://earthsky.org/.../everything-you-need-to-know... and https://amsmeteors.org/meteor.../meteor-shower-calendar/ for more on the Quadrantids. The major meteor showers occurring this year are discussed at https://www.skyandtelescope.com/observing/best-meteor-showers-in-2021/
Information on Iridium flares and passes of the ISS, the X-37B, the HST, Starlink, and other satellites can be found at http://www.heavens-above.com/
The Moon is 17.2 days old, is illuminated 97.0%, subtends 31.1 arc minutes, and is located in Gemini on January 1st at 0:00 UT. New Moon occurs on December 13th. Favorable librations for the following lunar features occur on the indicated dates: Crater Inghirami on January 3rd, Crater Kircher on January 8th, Crater Bel'Kovich on January 19th, and Crater Pingre on January 31st. The Moon is at perigee (distance 57.60 Earth-radii) on January 9th and at apogee (distance 63.40 Earth-radii) on January 21st. The Maginus Lunar Sunrise Crater Light Ray is predicted to occur at 12:41 UT on January 21st. Browse http://www.lunar-occultations.com/iota/iotandx.htm for information on lunar occultation events. Visit https://saberdoesthestars.wordpress.com/.../saber-does.../ for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon06.html for Full Moon data. Consult http://time.unitarium.com/moon/where.html or download http://www.ap-i.net/avl/en/start for current information on the Moon. Visit https://www.fourmilab.ch/earthview/lunarform/lunarform.html for information on various lunar features and https://upload.wikimedia.org/.../600px-Moon_names.jpg... for a simple map of the Moon. See https://svs.gsfc.nasa.gov/4768 for a lunar phase and libration calculator and https://quickmap.lroc.asu.edu/?extent=-90,-25.2362636,90,25.2362636&proj=10&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1SizSg for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap. Click on https://www.calendar-12.com/moon_calendar/2021/january for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at http://www.lunar-occultations.com/rlo/rays/rays.htm
The Sun is located in Sagittarius on January 1st. It enters Capricornus on January 19th.
Data (magnitude, apparent size, illumination, and distance from the Earth in astronomical units) for the planets and Pluto on January 1st: Mercury (-1.0, 4.8", 98%, 1.39 a.u., Sagittarius), Venus (-3.9, 10.7", 94%, 1.56 a.u., Ophiuchus), Mars (-0.2, 10.4", 89%, 0.90 a.u., Pisces), Jupiter (-2.0, 32.9", 100%, 5.99 a.u., Capricornus), Saturn (+0.6, 15.2", 100%, 10.90 a.u., Capricornus), Uranus (+5.7, 3.6", 100%, 19.57 a.u. on January 16th, Aries), Neptune (+7.9, 2.2", 100%, 30.51 a.u. on January 16th, Aquarius), Pluto (+14.4, 0.1", 100%, 35.18 a.u. on January 16th, Sagittarius).
During the evening, Mars and Uranus in the south, Mercury and Neptune lie in the southwest, and Jupiter and Saturn in the west. At midnight, Mars and Uranus are in the west. Venus can be seen in the southeast in the morning.
Mercury, Jupiter, and Saturn lie within a circle with a diameter of 2.4 degrees on January 10th. On the evening of January 13th (January 14th UT), the Moon, Mercury and Saturn lie within a circle with a diameter of 6.0 degrees, the Moon, Jupiter, and Saturn lie within a circle with a diameter of 3.8 degrees, and the Moon, Mercury and Jupiter lie within a circle with a diameter of 4.0 degrees. The Moon, Mars, and Uranus lie within a circle with a diameter of 4.6 degrees on January 21st.
Mercury is at its greatest heliocentric latitude south on January 5th. It returns to the evening sky at twilight after January 8th and is 1.6 degrees southeast of Saturn on January 10th. Mercury is 1.4 degrees southeast of Jupiter on January 11th. The speediest planet is located 2.3 degrees north of the young Moon on January 14th. Mercury is at greatest eastern elongation, the second best of 2021, on January 23rd (January 24th UT). Mercury sets about 90 minutes after the Sun and shines at magnitude -0.6 on that date. Mercury reaches perihelion on January 29th. On that date, it is also stationary and subsequently begins to retrograde.
Venus grows increasingly more difficult to observe at January progresses. It rises more than an hour before sunrise on January 1st but only about 30 minutes before the Sun rises as January ends. Venus lies between M8 (the Lagoon Nebula) and M20 (the Trifid Nebula) on the morning of January 9th. A slender waning crescent Moon passes 1.5 degrees south of the brightest planet on January 11th. Venus is at its southernmost declination on January 12th. The prominent globular cluster M22 lies 46 arc minutes south of Venus on January 15th.
Earth is 0.9833 a.u. distant from the Sun at perihelion on January 2nd. On that date, it’s about 3% (5.0 million kilometers or 3.1 million miles) closer to the Sun than at aphelion on July 5th and about 2.7% closer to the Sun than on average.
Mars begins the month with a brightness of magnitude -0.2 and an apparent diameter of 10.4 arc seconds. It is illuminated 89% for the entire month. As January begins, Mars is near the sixth-magnitude star Pi Piscium. The Red Planet departs Pisces and enters Aries on January 5th. Mars passes within six degrees of the fourth-magnitude star Mesarthim (Gamma Arietis) on January 13th. Mars and Uranus are less than two degrees apart from January 18th to January 22nd. On January 21st, Mars is located 1.7 degrees due north of Uranus. The waxing gibbous Moon passes 4.7 degrees southeast of Mars on that date. At month's end, Mars shines at only magnitude +0.4 and subtends just 7.9 arc seconds.
Jupiter and Saturn are steadily growing apart since the historic conjunction on December 21st and are 1.3 degrees apart on January 1st. By January 7th, the two gas giant planets are separated by two degrees. The young crescent Moon passes 3.3 degrees southeast of Jupiter on January 14th. Jupiter is in conjunction with the Sun on January 29th.
Saturn can be seen during evening twilight until January 7th. The very young crescent Moon passes 3.2 degrees southeast of Saturn on January 13th. The Ringed Planet is in conjunction with the Sun on January 24th.
Uranus is located about half-way between fifth-magnitude star Xi Arietis and the sixth-magnitude 19 Arietis. The waxing gibbous Moon passes 3.1 degrees southeast of Uranus on January 21st. Uranus is at eastern quadrature on January 26th. Visit http://www.nakedeyeplanets.com/uranus.htm for a finder chart.
Neptune is located one degree east of the fourth-magnitude star Phi Aquarii. The waxing crescent Moon passes 4.1 degrees southeast of Neptune on January 17th. The eighth planet sets before 9:00 p.m. local time as January ends. Browse http://www.nakedeyeplanets.com/neptune.htm for a finder chart.
Finder charts for Uranus and Neptune are also available online at https://skyandtelescope.org/.../UranusNeptune2020_BW...
See http://www.curtrenz.com/uranep.html for additional information on the two outer planets.
Click on http://www.skyandtelescope.com/.../interactive-sky.../ for JavaScript utilities that will illustrate the positions of the five brightest satellites of Uranus and the position of Triton, Neptune’s brightest satellite.
The dwarf planet Pluto is in conjunction with the Sun on January 14th.
For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/
A guide to planetary observing for the year by the British magazine The Sky at Night is posted at https://www.skyatnightmagazine.com/.../astronomy-guide.../
Asteroid 16 Psyche shines at tenth magnitude as it glides northwestward through Taurus about 1.5 degrees north of Aldebaran. Asteroids brighter than magnitude +11.0 that reach opposition this month include 15 Eunomia (magnitude +8.4), the largest stony asteroid, on January 21st, 14 Irene (magnitude +9.3) on January 24th, and 10 Hygiea (magnitude +9.9) on January 28th. See http://asteroidoccultation.com/2021_01_si.htm for information on asteroid occultation events taking place this month. Consult http://www.curtrenz.com/asteroids.html to learn more about a number of various asteroids.
During January, Comet 88P/Howell travels northeastward through Aquarius this month. The faint periodic comet passes relatively close to Neptune by the end of January. The fragmented Comet 141P/Machholz 2 heads towards Mira (Omicron Ceti) from the vicinity of Neptune this month. Comet 17P/Holmes, which brightened to second magnitude in 2007, lies to the west of Comet 88P/Howell. Visit http://cometchasing.skyhound.com/ and http://www.aerith.net/comet/future-n.html and https://cobs.si/ for information on these and other comets visible this month.
A wealth of information on solar system celestial bodies is posted http://nineplanets.org/ and http://www.curtrenz.com/astronomy.html
Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtelescope.com/observing/sky-at-a-glance/
An article titled Sky Highlights for 2021 appears on pages 48-50 of the January 2021 issue of Sky & Telescope.
Another article on some of the astronomical events taking place in the coming year can be found at https://www.universetoday.com/.../astronomy-2021-top.../
Free star maps for January can be downloaded at http://www.skymaps.com/downloads.html and http://www.telescope.com/content.jsp...
Omicron2 (40) Eridani is a fourth-magnitude triple star system consisting of three dwarf stars: a type K1V yellow-orange dwarf known as Keid, a type DA4 white dwarf, and a type M4.5e red dwarf. Omicron is located about 16 light years from the Earth at 4h15m16.32s, -7°39'10.34?. Ninth-magnitude Omicron B is the most easily visible white dwarf star and can be seen with an aperture of six inches.
The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on January 3rd, 6th, 9th, 12th, 15th, 18th, 21th, 23rd, 26th, and 29th. The Demon Star is at minimum brightness for approximately two hours and is well-placed for observers in North America on the night of January 15th, centered at 2:12 a.m. EST. Minima can also be observed on the night of January 17th, centered at 11:01 p.m. EST, and on the evening of January 20th, centered at 7:50 p.m. EST. Consult page 50 of the January 2021 issue of Sky & Telescope for the times of the minima. See http://stars.astro.illinois.edu/sow/Algol.html and http://www.solstation.com/stars2/algol3.htm for more on Algol.
Data on current supernovae can be found at http://www.rochesterastronomy.org/snimages/
Information on observing some of the more prominent Messier galaxies is available at http://www.cloudynights.com/.../358295-how-to-locate.../
Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and https://www.cambridge.org/.../seasonal_skies_january-march
Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.custerobservatory.org/docs/messier2.pdf and http://sao64.free.fr/observations/catalogues/cataloguesac.pdf
Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas), which also includes information on purchasing binoculars, at http://www.philharrington.net/tuba.htm
Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start
Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and https://telescopius.com/ and http://tonightssky.com/MainPage.php
Freeware sky atlases can be downloaded at http://www.deepskywatch.com/.../Deep-Sky-Hunter-atlas... and https://www.cloudynights.com/.../free-mag-7-star-charts... and https://allans-stuff.com/triatlas/
One hundred and five binary and multiple stars for January: Omega Aurigae, 5 Aurigae, Struve 644, 14 Aurigae, Struve 698, Struve 718, 26 Aurigae, Struve 764, Struve 796, Struve 811, Theta Aurigae (Auriga); Struve 485, 1 Camelopardalis, Struve 587, Beta Camelopardalis, 11 & 12 Camelopardalis, Struve 638, Struve 677, 29 Camelopardalis, Struve 780 (Camelopardalis); h3628, Struve 560, Struve 570, Struve 571, Struve 576, 55 Eridani, Struve 596, Struve 631, Struve 636, 66 Eridani, Struve 649 (Eridanus); Kappa Leporis, South 473, South 476, h3750, h3752, h3759, Beta Leporis, Alpha Leporis, h3780, Lallande 1, h3788, Gamma Leporis (Lepus); Struve 627, Struve 630, Struve 652, Phi Orionis, Otto Struve 517, Beta Orionis (Rigel), Struve 664, Tau Orionis, Burnham 189, h697, Struve 701, Eta Orionis, h2268, 31 Orionis, 33 Orionis, Delta Orionis (Mintaka), Struve 734, Struve 747, Lambda Orionis, Theta-1 Orionis (the Trapezium), Theta-2 Orionis, Iota Orionis, Struve 750, Struve 754, Sigma Orionis, Zeta Orionis (Alnitak), Struve 790, 52 Orionis, Struve 816, 59 Orionis, 60 Orionis (Orion); Struve 476, Espin 878, Struve 521, Struve 533, 56 Persei, Struve 552, 57 Persei (Perseus); Struve 479, Otto Struve 70, Struve 495, Otto Struve 72, Struve 510, 47 Tauri, Struve 517, Struve 523, Phi Tauri, Burnham 87, Xi Tauri, 62 Tauri, Kappa & 67 Tauri, Struve 548, Otto Struve 84, Struve 562, 88 Tauri, Struve 572, Tau Tauri, Struve 598, Struve 623, Struve 645, Struve 670, Struve 674, Struve 680, 111 Tauri, 114 Tauri, 118 Tauri, Struve 730, Struve 742, 133 Tauri (Taurus)
Notable carbon star for January: R Leporis (Hind’s Crimson Star)
Seventy deep-sky objects for January: B26-28, B29, M36, M37, M38, NGC 1664, NGC 1778, NGC 1857, NGC 1893, NGC 1907, NGC 1931 (Auriga); IC 361, Kemble 1 (Kemble’s Cascade asterism), NGC 1501, NGC 1502, NGC 1530, NGC 1569 (Camelopardalis); NGC 1507, NGC 1518, NGC 1531, NGC 1532, NGC 1535, NGC 1537, NGC 1600, NGC 1637, NGC 1659, NGC 1700 (Eridanus); IC 418, M79, NGC 1832, NGC 1888, NGC 1964 (Lepus); B33, Cr65, Cr69, Cr70, IC 434, M42, M43, M78, NGC 1662, NGC 1973-75-77, NGC 1981, NGC 1999, NGC 2022, NGC 2023, NGC 2024, NGC 2112 (Orion); Be11, NGC 1491, NGC 1496, NGC 1499, NGC 1513, NGC 1528, NGC 1545, NGC 1548, NGC 1579, NGC 1582, NGC 1605, NGC 1624 (Perseus); DoDz3, DoDz4, M1, Mel 25, NGC 1514, NGC 1587, NGC 1647, NGC 1746, NGC 1807, NGC 1817 (Taurus)
Top ten binocular deep-sky objects for January: Cr65, Kemble 1, M36, M37, M38, M42, NGC 1528, NGC 1647, NGC 1746, NGC 1981
Top ten deep-sky objects for January: M1, M36, M37, M38, M42, M43, M78, M79, NGC 1501, NGC 2024
Challenge deep-sky object for January: IC 2118 (Eridanus)
The objects listed above are located between 4:00 and 6:00 hours of right ascension.
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Minor Planet Occultation Updates:
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