Astronomy_News_20_08_2020
Astronomy_News_20_08_2020
This months research Papers 20_08_2020
RASNZ_20_08_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
Surface and oceanic habitability of Trappist-1 planets under the impact of flares
https://arxiv.org/abs/2008.09147
Magma ocean evolution of the TRAPPIST-1 planets
https://arxiv.org/abs/2008.09599
Potential For Liquid Water Biochemistry Deep Under The Surfaces Of The Moon, Mars And Beyond
https://arxiv.org/abs/2008.08709
Isotopically distinct terrestrial planets via local accretion
https://arxiv.org/abs/2008.08850
High-resolution survey for planetary companions to young stars in the Taurus Molecular Cloud
https://arxiv.org/abs/2008.06065
Quantifying the information impact of future searches for exoplanetary biosignatures
https://arxiv.org/abs/2008.07586
Detection of ten new planets
https://arxiv.org/abs/2008.07998
Missions to and Sample Returns from Nearby Interstellar Objects
https://arxiv.org/abs/2008.07647
An eclipsing M-dwarf close to the hydrogen burning limit from NGTS
https://arxiv.org/abs/2008.07354
Powering the Galilean Satellites with Moon-Moon Tides
https://arxiv.org/abs/2008.02825
The Science Case for a Titan Flagship-class Orbiter with Probes
https://arxiv.org/abs/2008.05680
Optical Transmission Spectroscopy of the Terrestrial Exoplanet LHS 3844b
https://arxiv.org/abs/2008.05444
Effects of Flux Variation on the Surface Temperatures of Earth-like Circumbinary Planets
https://arxiv.org/abs/2008.04992
Could the Migration of Jupiter have Accelerated the Atmospheric Evolution of Venus
https://arxiv.org/abs/2008.04927
Differing Enceladean ocean circulation and ice shell geometries driven by tidal heating
https://arxiv.org/abs/2008.03764
Non-detection of O2/O3 informs frequency of Earth-like planets with LUVOIR but not HabEx
https://arxiv.org/abs/2008.03952
Water worlds in N-body simulations with fragmentation in systems without gaseous giants
https://arxiv.org/abs/2008.03594
Monte Carlo estimation of the probability of causal contacts between communicating civilisations
https://arxiv.org/abs/2007.03597
A Long-Lived Sharp Disruption on the Lower Clouds of Venus
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL087221
The Habitable-zone Planet Finder Reveals A High Mass and a Low Obliquity for the Young Neptune K2-25b
https://arxiv.org/abs/2007.12766
https://www.centauri-dreams.org/2020/08/07/a-dense-sub-neptune-challenges-formation-theories/
An astrometric planetary companion candidate to the M9 Dwarf TVLM 513-46546
https://arxiv.org/abs/2008.01595
https://www.centauri-dreams.org/2020/08/05/saturn-class-exoplanet-is-a-win-for-astrometry/
http://spaceref.com/extrasolar-planets/radio-telescopes-find-extrasolar-planet-around-main-sequence-star.html
The Habitability of the Galactic Bulge
https://arxiv.org/abs/2008.01419
Stellar Pulsation and the Production of Dust and Molecules in Galactic Carbon Stars
https://arxiv.org/abs/1910.11401
Prebiotic precursors of the primordial RNA world in space
https://arxiv.org/abs/2008.00228
Exoplanets Sciences with Nulling Interferometers and a Single-Mode Fiber-Fed Spectrograph
https://arxiv.org/abs/2007.15529
Asteroid impact, Schumann resonances and the end of dinosaurs
https://arxiv.org/abs/2007.15463
Observing Earth from the Moon to prepare for detecting life on Earth-like exoplanets
https://arxiv.org/abs/2007.16078
Dynamical Packing in the Habitable Zone
https://arxiv.org/abs/2006.13962
The stability of tightly-packed, evenly-spaced systems of Earth-mass planets orbiting a Sun-like star
https://arxiv.org/abs/1703.08426
https://www.centauri-dreams.org/2020/08/04/a-tight-fit-planets-in-the-habitable-zone/
Oceanic and atmospheric methane cycling in the cGENIE Earth system model
https://arxiv.org/abs/2007.15053
Colors of an Earth-like exoplanet
https://arxiv.org/abs/2007.15624
investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface
https://www.nature.com/articles/s41598-020-68715-7
Near-parabolic comets observed in 2006-2010
https://arxiv.org/abs/1308.0563
No evidence for interstellar planetesimals trapped in the Solar System
https://arxiv.org/abs/2006.04534
The Science Case for Spacecraft Exploration of the Uranian Satellites
https://arxiv.org/abs/2007.07284
Can Volcanism Build Hydrogen-Rich Early Atmospheres
https://arxiv.org/abs/2007.12037
Using a real-world network to model localized COVID-19 control strategies
https://www.nature.com/articles/s41591-020-1036-8
Deforestation and world population sustainability: a quantitative analysis
https://www.nature.com/articles/s41598-020-63657-6
https://www.vice.com/en_us/article/akzn5a/theoretical-physicists-say-90-chance-of-societal-collapse-within-several-decades
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Interesting News items
New Zealand Astrophotography Weekend 2020
http://www.horoastronomy.org.nz/upcoming-events/astrophotography-weekend
'Shallow Lightning' and 'Mushballs' Reveal Ammonia to NASA's Juno Scientists
https://www.jpl.nasa.gov/news/news.php?feature=7721
Vincent Van Gogh’s art comes alive and larger than life on Wellington waterfront
https://www.stuff.co.nz/entertainment/122282691/vincent-van-goghs-art-comes-alive-and-larger-than-life-on-wellington-waterfront
The People’s Space Odyssey: 2010: The Year We Make Contact
https://www.centauri-dreams.org/2020/07/31/the-peoples-space-odyssey-2010-the-year-we-make-contact/
The scramble for space at Earth’s outer limits
https://www.rnz.co.nz/news/world/423083/the-scramble-for-space-at-earth-s-outer-limits
The Unraveling of America
https://www.rollingstone.com/politics/political-commentary/covid-19-end-of-american-era-wade-davis-1038206
Hi,
As most of you know, there's been a nice, bright comet in Northern Hemisphere skies lately. It's now just heading into NZ's low NW twilight sky after sunset.
I imaged it tonight (2020 Jul 29, ~6:30pm NZST) with a 35cm f10 SCT and CCD. It was only about 12 degrees in altitude and quite thick high cloud was over it. Nonetheless, the stacked images show the fuzzball - which was too faint to see visually. Image attached. The ephemerides from GUIDE 9 is (the magnitude is very approximate) -
NEOWISE (C/2020 F3)
Date RA declination r delta mag Elong Speed PA Con
---- -- ----------- - ----- --- ----- ------ ----- ---
30 Jul 2020 12h07m12.44s +32 41' 07.8" 0.7726 0.7471 5.4 49.2 468.12 130.3 Com
31 Jul 2020 12h17m56.88s +30 41' 07.6" 0.7943 0.7641 5.6 50.7 445.32 132.0 Com
1 Aug 2020 12h27m42.19s +28 43' 39.9" 0.8158 0.7829 5.8 52.0 422.32 133.4 Com
2 Aug 2020 12h36m34.63s +26 49' 38.0" 0.8373 0.8033 6.0 53.3 399.54 134.6 Com
3 Aug 2020 12h44m40.02s +24 59' 38.8" 0.8586 0.8252 6.2 54.5 377.31 135.7 Com
4 Aug 2020 12h52m03.64s +23 14' 05.6" 0.8798 0.8484 6.4 55.5 355.89 136.6 Com
5 Aug 2020 12h58m50.22s +21 33' 11.1" 0.9009 0.8727 6.6 56.4 335.44 137.3 Com
6 Aug 2020 13h05m03.99s +19 56' 59.7" 0.9218 0.8981 6.8 57.2 316.07 138.0 Com
7 Aug 2020 13h10m48.63s +18 25' 29.8" 0.9426 0.9244 7.0 58.0 297.83 138.5 Com
8 Aug 2020 13h16m07.41s +16 58' 35.2" 0.9633 0.9516 7.2 58.6 280.74 139.0 Com
9 Aug 2020 13h21m03.20s +15 36' 06.9" 0.9839 0..9794 7.4 59.1 264.79 139.4 Com
10 Aug 2020 13h25m38.49s +14 17' 53.6" 1.0043 1.0079 7.5 59.6 249.93 139.7 Vir
11 Aug 2020 13h29m55.47s +13 03' 42.9" 1.0246 1.0369 7.7 59.9 236.14 139.9 Vir
12 Aug 2020 13h33m56.08s +11 53' 22.0" 1.0448 1.0665 7.9 60.2 223.34 140.1 Vir
13 Aug 2020 13h37m42.00s +10 46' 37.8" 1.0649 1.0965 8.1 60.5 211.48 140.2 Boo
14 Aug 2020 13h41m14.72s +09 43' 17.2" 1.0849 1.1268 8.2 60.6 200.49 140.3 Boo
15 Aug 2020 13h44m35.55s +08 43' 07.6" 1.1048 1.1575 8.4 60.8 190.32 140.4 Boo
16 Aug 2020 13h47m45.64s +07 45' 57.1" 1.1245 1.1884 8.5 60.8 180.90 140.4 Boo
17 Aug 2020 13h50m46.01s +06 51' 34.0" 1.1441 1.2196 8.7 60.8 172.18 140.4 Vir
18 Aug 2020 13h53m37.58s +05 59' 47.5" 1.1636 1.2510 8.8 60.8 164.10 140.3 Vir
19 Aug 2020 13h56m21.15s +05 10' 27.5" 1.1831 1.2826 9.0 60.7 156.61 140.2 Vir
20 Aug 2020 13h58m57.43s +04 23' 24.4" 1.2024 1.3143 9.1 60.6 149.66 140.1 Vir
21 Aug 2020 14h01m27.06s +03 38' 29.4" 1.2216 1.3461 9.3 60.4 143.21 140.0 Vir
22 Aug 2020 14h03m50.61s +02 55' 34.1" 1.2407 1.3780 9.4 60.3 137.21 139.8 Vir
23 Aug 2020 14h06m08.58s +02 14' 30.8" 1.2597 1.4100 9.5 60.0 131.63 139.7 Vir
24 Aug 2020 14h08m21.45s +01 35' 12.6" 1.2786 1.4420 9.7 59.8 126.44 139.5 Vir
25 Aug 2020 14h10m29.61s +00 57' 32.7" 1.2974 1.4741 9.8 59.5 121.60 139.3 Vir
26 Aug 2020 14h12m33.44s +00 21' 25.0" 1.3161 1.5061 9.9 59.2 117.08 139.0 Vir
27 Aug 2020 14h14m33.28s -00 13' 16.1" 1.3347 1.5382 10.1 58.9 112.87 138.8 Vir
28 Aug 2020 14h16m29.42s -00 46' 36.0" 1.3532 1.5703 10.2 58.6 108.93 138.5 Vir
29 Aug 2020 14h18m22.15s -01 18' 39.6" 1.3716 1.6023 10.3 58..2 105.25 138.3 Vir
Cheers
John D
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Updates from Andrew B,
Betelgeuse / Alpha Orionis, the mystery of the 2019 - 2020 dimming deepens further.
Seems odd to bring this up now, August 2020 (now visible before sunrise), as Betelgeuse / Alpha Orionis is best seen in the northern hemisphere from November to April, however new, very unique observations have recently been released.
NASA’s Solar and Terrestrial Relations Observatory / STEREO spacecraft in June and July was able to observe Betelgeuse due to it's position, some 70 degrees behind Earth, so whilst Betelgeuse from Earth was practicaly invisible being only just 16 degrees south of the Sun on 20th June, from STEREO's position, was still visible as the Stereo spacecraft's position was roughly where Earth's was in mid April.
The STEREO spacecraft observed Betelgeuse on five separate days, the the spacecraft was rolled for about two hours each time to place Betelgeuse in the field of view of STEREO’s Heliospheric Imager, an instrument usually used to capture images of the Sun’s solar wind, as it passes by the spacecraft and towards Earth.
What was found was that Betelgeuse was dimming again unexpectedly.
First it was thought to be due to carbon rich dust being ehected, then due to giganituc starspots and now again the opinion is back to dust clouds, possibly a gigantic Coronal Mass Ejection from Betelgeuse, a hot spot ejecting gas and dust, that then cooled causing dimming based on Hubble Space Telescope data from last year. I wonder if, it could be both?
There is a general five year brightness cycle with this gigantic, dying red supergiant star, but this particular dimming was very unusual, for a few days in early February 2020, was actually the third brightest star in Orion (just dipping below Bellatrix / Gamma Orionis in brightness) certainly the dimmest I had ever seen Betelgeuse. I have known Orion the Hunter since I was about five (1974), never do I remember seeing Betelgeuse dim like this before.
Betelgeuse lies about 643 light years away from our Solar system, so the light reaching us in 2020 left Betelgeuse in the year 1377 and the strange dimmings actually happened in 1376 & 1377 and has a spectrum M2, so very red.
Betelgeuse / Alpha Orionis has a mass of approximately 19.7 times greater than our Sun or about 6.6 million times that of the Earth. Our Sun by contrast has a mass of 332,946 Earths.
The diameter of Betelgeuse is about 1.329 Billion KM / 825.802 million miles or some 955 times that of our Sun or 104,100 times that of the Earth. Our Sun is much smaller at 1,391,400 KM / 864,600 miles wide or 109 times wider than the Earth.
Betelgeuse takes about 17 years to rotate on it's axis as against 25 days for our own Sun.
Text: Andrew R Brown.
NASA / Goddard Spaceflight Centre / STEREO / HI.
Jupiter.
Imaged: Saturday 25th July 2020.
Thunderstorms (centre of image), seen during the Perijove 28 JUNO Spacecraft pass.
Perijove is the closest point to Jupiter in a Jovecentric (Jupiter centred) orbit.
Citizen scientist, Kevin M Gill, created the main image using data from the JUNO spacecraft's JunoCam instrument. This view is a map projection.
A diagram showing how a Jupiter 'mushball' thunderstorm works and an illustration using Steller Reference Unit camera image data, colourized using JUNOCAM data with lightning flashes added in situ.
The JUNO spacecraft passed through Perijove from North to South at a speed of about 217,200 KPH / 135,000 MPH or 177.33 times faster than the speed of sound through normal air pressure.
It has been postulated that within some of Jupiter's, Saturn's and Neptune's gigantic storms that some hailstones could be up to at least the size of cars and thunderclaps so loud that if Earth thunderstorms had lightning so powerful that could create thunder that would demolish entire cities, and could be heard from hundreds of kilometres / miles away, for example: Jovian thunderstorm over London, UK, could be heard from Oslo, Norway or Rome, Italy or Madrid, Spain!!!!
A new type of jovian hailstone has also been identified. It is tentatively called a 'Mushball'. This also solves another mystery. Whilst Jupiter has huge swathes of high altitude ammonia ice cirrus clouds at Jupiter's tropopause (the boundary of the troposiphere and stratosphere in the atmosphere of Jupiter), there appears to be a general (not total) lack of ammonia in Jupiter's atmosphere in a gaseous form.
Mushballs appear to start as regular water hailstones deeper in Jupiter's troposphere near the base of gigantic thunderstorms some 65 KM / 40 miles below the visible regular cloud deck where temperatures are above 0 Celsius / 32 Fahrenheit. As the hailstones rise on the powerful updrafts (up to about 500 KPH / 311 MPH), they meet ammonia and the ammonia acts at an antifreeze as the hailstone reaches higher in the thunderstorm, some 26 KM / 16 miles higher up where temperatures drop below minus 100 Celsius / minus 148 Fahrenheit. The ice becomes mushy hense mushball. The mushball descends and then picks up another layer of regular water ise which freezes solid and the updrafts allow it to pick up more ammonia, so the mushball grows. Some of these thunderstorms can grow to about 80 KM / 50 miles in height. The mushballs like regular hail get too heavy and then plummet deep into Jupiter's troposphere, where they melt into ammonia / water rain and then evaporate the begin the cycle again.
Another mystery solved appears to be 'shallow' lightning near the tops of some of Jupiters gigantic thunderstorms. The Stellar Reference Unit camera which is used for navigation using the stars has also been effective at imaging phenomena in Jupiter's atmosphere over the nightside, sometimes lit faintly by the reflected sunlight off the Galilean moons, particularly Io and Europa.The Stellar Reference Unit camera had found some lightning literally just below the tops of the anvils of some of these colosal jovian cumulonimbus clouds, and that cannot be explained by regular ice crystals and hailstones alone.
Mushballs explain that mystery too as mushballs are lighter then regular all water hailstones, so they can produce lighting higher up. Jupiter certainly does have deep lightning too produced by varying sizes of frozen water from tiny ice crystals, snowflakes, and hail, some of which may be the size of cars.
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, hense 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, which traps and accelerates particles and electrons 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), almost 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, hense radiation hardened spacecraft are needed to approach these two fascinating and very different moons (Io, highly volcanic, with lava lakes and some of the solar systems tallest mountains and Europa with an ice crust over potential oceans).
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, only survived by it's immense speed through the Jovian system, but it was a very close call. However this finding meant all future spacecraft closely approaching Jupiter and the inner moons (inside the orbit of the giant moon Ganymede) would have to 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 and are likely captured asteroids and comets) are all outside of the radiation belts.
Text: Andrew R Brown.
JunoCam.
NASA / JPL-Caltech / SWRI / Malin Space Science Systems. JUNO spacecraft. Kevin M Gill.
Mars Perseverance Rover, doing well despite Safing Event shortly after launch from Earth.
A perfect launch was performed by the ULA / United Space Alliance, Atlas 5 from Launch Complex 41 at Kennedy Space Centre, Florida, USA.
The Atlas 5 left the pad 1/10,000th of a second early, giving the Perseverance Rover & the experimental Ingenuity Helicopter in the capsule attached to the Cruise Stage a ride into space.
Druing the latter part of the Centaur burn, the spacecraft entered the Earth's shadow (passed over the sunset terminator) over the Indian Ocean, just to the southwest of Sri Lanka & India After spacecraft separation, which also occured whilst still in Earth's shadow, the Perseverance Rover went into Safe Mode. The higher functions shut down and the spacecraft called home.
The spacecraft sensed a drop in temperature that it was not expecting. Spacecraft components in Earth's shadow if not heated can drop to temperatures as low as minus 220 Celsius / minus 364 Fahrenheit, about the same as the average surface temperatures on the moons of the planet Uranus.
However Perseverance did not get as cold as that owing to the fact the time in Earth's shadow was quite short and also that Perseverance is powered by an MMRTG (Multi Mission Radioisotopic Thermoelectric Generator) that uses the natural decay of Plutonium 238 (element 94, atomic weight 238. 94 Protons, 144 Neutrons and 94 Electrons) which has a half life of 87 years and 9 months.
The reason for using an MMRTG over solar arrays is that Mars Perseverance Rover like her cousin already on Mars since August 2012, Mars Science Laboratory Curiosity is that both use a large array of insruments as well as heavy duty drive motors. The amount of sunlight reaching Mars averages only 44% as that on Earth and the Moon. Solar arrays are fine for smaller rovers like the now inactive Mars Exploration Rovers Spirit & Opportunity (both of which were eventually killed off due to cold and also Opportunity was killed off by a dust storm and dust settling on the arrays) and for fixed landers like the now inactive Mars Pathfinder and Mars Phoenix Lander and the currently operating Mars InSight Lander.
Solar arrays simply were not up to the task for this particular mission or for Mars Science Laboratory Curiosity. The Cruise Stage however is solar powered.
Contrary to sensationalist media reports, Mars Perseverance Rover is not nuclear powered, as no nuclear reactions are taking place, therefore the MMRTG is not a nuclear reactor. It is actually a type of battery that converts heat from radioactive decay to electricity.
The temperature controller for the MMRTG (which used Freon for temperature management) detected the drop in temperature and triggered the spacecraft safing. After about three hours and after the Mars Perseverance Rover and Cruise Stage exited Earth's shadow and were back in full sunlight, engineers figured out the problem.
No damage was caused (that's why there are safing procedures programmed in) and the spacraft remains in excellent health after such a fantastic launch.
Text: Andrew R Brown.
United Launch Alliance.
Kowsky / UPI.
NASA / JPL-Caltech.
Mars Perseverance Rover, doing well despite Safing Event shortly after launch from Earth.
A perfect launch was performed by the ULA / United Space Alliance, Atlas 5 from Launch Complex 41 at Kennedy Space Centre, Florida, USA.
The Atlas 5 left the pad 1/10,000th of a second early, giving the Perseverance Rover & the experimental Ingenuity Helicopter in the capsule attached to the Cruise Stage a ride into space.
Druing the latter part of the Centaur burn, the spacecraft entered the Earth's shadow (passed over the sunset terminator) over the Indian Ocean, just to the southwest of Sri Lanka & India After spacecraft separation, which also occured whilst still in Earth's shadow, the Perseverance Rover went into Safe Mode. The higher functions shut down and the spacecraft called home.
The spacecraft sensed a drop in temperature that it was not expecting. Spacecraft components in Earth's shadow if not heated can drop to temperatures as low as minus 220 Celsius / minus 364 Fahrenheit, about the same as the average surface temperatures on the moons of the planet Uranus.
However Perseverance did not get as cold as that owing to the fact the time in Earth's shadow was quite short and also that Perseverance is powered by an MMRTG (Multi Mission Radioisotopic Thermoelectric Generator) that uses the natural decay of Plutonium 238 (element 94, atomic weight 238. 94 Protons, 144 Neutrons and 94 Electrons) which has a half life of 87 years and 9 months.
The reason for using an MMRTG over solar arrays is that Mars Perseverance Rover like her cousin already on Mars since August 2012, Mars Science Laboratory Curiosity is that both use a large array of insruments as well as heavy duty drive motors. The amount of sunlight reaching Mars averages only 44% as that on Earth and the Moon. Solar arrays are fine for smaller rovers like the now inactive Mars Exploration Rovers Spirit & Opportunity (both of which were eventually killed off due to cold and also Opportunity was killed off by a dust storm and dust settling on the arrays) and for fixed landers like the now inactive Mars Pathfinder and Mars Phoenix Lander and the currently operating Mars InSight Lander.
Solar arrays simply were not up to the task for this particular mission or for Mars Science Laboratory Curiosity. The Cruise Stage however is solar powered.
Contrary to sensationalist media reports, Mars Perseverance Rover is not nuclear powered, as no nuclear reactions are taking place, therefore the MMRTG is not a nuclear reactor. It is actually a type of battery that converts heat from radioactive decay to electricity.
The temperature controller for the MMRTG (which used Freon for temperature management) detected the drop in temperature and triggered the spacecraft safing. After about three hours and after the Mars Perseverance Rover and Cruise Stage exited Earth's shadow and were back in full sunlight, engineers figured out the problem.
No damage was caused (that's why there are safing procedures programmed in) and the spacraft remains in excellent health after such a fantastic launch.
Text: Andrew R Brown.
United Launch Alliance.
Kowsky / UPI.
NASA / JPL-Caltech.
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RASNZ
Royal Astronomical Society of New Zealand
eNewsletter: No. 236, 20 August 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. RASNZ Conference Cancelled
2. The Solar System in September
3. Variable Star News
4. New Zealand Astrophotography Competition - Closes September 21
5. Stargazers Getaway September 18-20
6. Intelligent Life Elsewhere?
7. Betelgeuse Dimming Explained
8. Saturn-mass Exoplanet Found by Radio Astronomers
9. Cool Nearby Brown Dwarfs Discovered
10. Tiny asteroid Whizzes Past
11. Arecibo Radio Telescope Damaged
12. Quote
1. RASNZ Conference Cancelled
It is with great regret that we have to inform you that the 2020 RASNZ
Conference, AGM and associated meetings will not go ahead in person as
planned in October. This decision was driven largely by the recent return
to heightened travel restrictions and isolation measures in response to the re-emergence of Covid-19.
Our Society has a responsibility to manage its affairs in light of current Government policy and prevailing health advice regarding novel coronavirus covid-19. We do not want to expose our Members or guests to any unnecessary risk of infection or financial or other impact in the event of any last minute cancellation due to the fluctuating nature of alert levels.
We do aim however to hold the AGM on-line. We hope to include other online events including networking opportunities for our younger members. We will be in touch in due course with details once they are finalised.*
-- Nicholas Rattenbury and the RASNZ Council.
2. The Solar System in September
Dates and times shown are NZST (UT + 12 hours) up to September 26, NZDT (UT + 13 hours) from September 27. 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 SEPTEMBER, Rise & Set Magnitude & Constellation
SEP 1 NZST SEP 30 NZDT
Mag Cons Rise Set Mag Cons Rise Set
SUN -26.7 Leo 6.43am 5.58pm -26.7 Vir 6.54am 7.27pm
Merc -0.6 Leo 7.19am 7.02pm -0.0 Vir 7.43am 9.43pm
Venus -4.3 Gem 4.27am 2.16pm -4.1 Leo 5.20am 4.01pm
Mars -1.8 Psc 9.43pm 9.05am -2.5 Psc 8.38pm 8.02am
Jup -2.6 Sgr 1.22pm 4.24am -2.4 Sgr 12.29pm 3.31am
Sat 0.3 Sgr 2.04pm 4.53am 0.5 Sgr 1.07pm 3.57am
Uran 5.7 Ari 10.56pm 9.20am 5.7 Ari 9.59pm 8.25am
Nep 7.8 Aqr 6.38pm 7.22am 7.8 Aqr 5.40pm 6.26am
Pluto 14.5 Sgr 1.45pm 4.46am 14.5 Sgr 12.49pm 3.51am
SEPTEMBER 1 NZST SEPTEMBER 30 NZDT
Twilights morning evening morning evening
Civil: start 6.18am, end 6.24pm start 6.29am, end 7.53pm
Nautical: start 5.46am, end 6.56pm start 5.56am, end 8.26pm
Astro: start 5.14am, end 7.28pm start 5.23am, end 9.00pm
SEPTEMBER PHASES OF THE MOON, times NZST & UT
Full Moon: Sep 2 at 5.22pm (05:22 UT)
Last quarter: Sep 10 at 9.26pm (09:26 UT)
New Moon: Sep 17 at 11.00pm (11:00 UT)
First quarter: Sep 24 at 1.55pm (01:55 UT)
THE PLANETS in SEPTEMBER
MERCURY is visible in the early evening sky, setting more than 2 hours after the Sun from the 20th onward. With a magnitude 0.0 it will be quite easily visible, magnitude about 0, low to the west an hour after sunset.
On the evening of September 22 the planet will be only 20 arc-minutes (two-thirds the diameter of the full moon) from Spica, magnitude 1.1. Three evenings earlier, on the 19th, the crescent moon will be 6° to the right of Mercury.
VENUS is a brilliant morning object rising more than 2 hours before the Sun early in the month. The planet is 19° north of the equator at first, so is fairly low to the northeast in NZ skies. By the end of September it will rise just over 90 minutes before the Sun. Venus will then have moved 6° to the south and so be a little higher in southern skies.
The crescent moon will be about 8° from Venus on the mornings of September 14 and 15.
MARS is in Pisces. Early in September it rises shortly before 10 pm, so best seen after midnight. By the end of September Mars rises earlier so will be well placed by late evening. The planet is getting bright, by the end of the month it is slightly brighter than Jupiter. The planet is stationary on September 10 (NZ time) at 5am.
The moon will be some 4° from Mars as seen from NZ late evening of September 6.
JUPITER and SATURN are both stationary during September, Jupiter on the 13th and Saturn on the 26th. As they start moving forward to the east again their apparent separation will start decreasing as Jupiter begins to catch up with Saturn. The two planets will be slow moving, just under 8° apart.
The moon will be just over a degree from Jupiter early evening on the 25th. They are closest about 7pm, just over a degree apart. Saturn is closest to the moon for the month some 14 hours later so after they set for NZ.
PLUTO remains between Jupiter and Saturn during September, somewhat closer to the latter. At magnitude 14.5 it will only be visible in a moderate telescope.
URANUS, in Aries, rises late evening during September. The moon is 4.5° from the planet at midnight on September 7. At magnitude 5.7, Uranus is an easy binocular object
NEPTUNE is at opposition on September 12, NZ time and so is visible almost the whole night. It will then be 28.9 AU, 4326 million km from the Earth. The moon passes Neptune twice in September, on the 3rd and on the 30th. The two will be separated by 3.9° both times.
POSSIBLE BINOCULAR ASTEROIDS in SEPTEMBER
SEP 1 NZST SEP 30 NZDT
Mag Cons transit Mag Cons transit
(1) Ceres 7.7 Aqr 12.27am 8.2 PsA 11.12p
(4) Vesta 8.4 Cnc 10.22am 8.4 Leo 10.18am
(8) Flora 9.9 Cet 4.28am 8.7 Cet 3.45am
CERES is at opposition on September 2 with a magnitude 7.7. It is well south of the Equator so high in southern skies and visible through the night. Early in the month, Ceres is a little under 7° from the magnitude 1.23 star Fomalhaut. On the 1st the almost full moon is 12° the opposite side of Ceres to Fomalhaut
VESTA is a morning object rising some 70 minutes before the Sun on the 1st and 100 minutes before sunrise on the 30th. Like Venus it is well north of the equator so low to the northwest. On the morning of the 23rd Vesta will be 2° to the lower left of Venus, but 50 minutes before sunrise the asteroid will only be 6° above the horizon.
FLORA is a morning object which brightens to become a possible binocular object by late September. On the 30th it rises at 10 pm NZDT. Flora will then be 1.35° from the 2.5 magnitude star Menkar, alpha Cet.
-- Brian Loader
3. Variable Star News
Catalogue of LMC Variables Stars
The Large Magellanic Cloud (LMC), at 160,000 light years away, is one of the nearest galactic objects to our own Milky Way system. It is a rich resource for research with its large number of multiple star systems, variable stars of different types and gas cloud regions where star formation is underway.
The standard resource for checking out variable stars is the General Catalogue for Variable Stars (GCVS) and in the case of the LMC it is GCVS Vol. V. Extragalactic Variables, Catalogue of 4801 Variables, VizieR CDS II/214A edited by N N Samus (1995, 2002). More recently data was released from surveys by the European Space Agency (ESA) space mission Gaia project detailing positions of stars in the Magellanic cloud. Mati Morel used this data to check and update the positions of the variable stars in the catalogue. The positions of the variable since the stars were catalogued were updated to epoch 2000 and consulting original sources uncovered a number of transcription errors.
A detailed report on the project is given in the 2020 No 3 (July) issue of the VSS Newsletter. (Newsletters are available at the website). Mati notes that some stars in the GCVS were difficult to identify and notes on some of these are included in the papers.
The first project by Mati on the LMC stars was identification of the positions of five Novae reported from 1926 to 1951 which was published in the 2019 No3 (July) issue of the VSS Newsletter. Charts and positions, relative to Gaia DR2, are included in this article.
Mati Morel has a long history of meticulous work in the variable star field. For many years he produced easy to read drawings of star fields for the charts issued by the variable star observing section of RASNZ.
Mati acknowledges the use of the VizieR service of CDS, Strasbourg, and also the SIMBAD database, without which this work would hardly have been even contemplated. References are given to the sources used.
The full catalogue, LMC_VARS_4801.DAT is now available for use and is accessible on the VSS Databases & Cata¬logues page: https://www.variablestarssouth.org/member-contributed-catalogues/
-- Alan Baldwin
4. 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.
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
5. 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.
Guest speakers are ex Green MP Gareth Hughes, Amadeo Enriquez-Ballestero from the Otago Museum and their inflatable planetarium, and Alan Gilmore on the history of Mt John Observatory.
Numbers will be limited due to us currently being at Covid-19 Level 2.
For details see
https://www.facebook.com/events/943327669369996/
6. Intelligent Life Elsewhere?
For a lively and authoritative discussion on the possibilities of intelligent life elsewhere in the universe listen to Jesse Mulligan's interview with Dr Stephen Curran, astrophysics lecturer, Victoria University of Wellington at https://www.rnz.co.nz/national/programmes/afternoons/audio/2018759836/expert-feature-aliens-is-there-life-out-there
7. Betelgeuse Dimming Explained
New observations by the NASA/ESA Hubble Space Telescope suggest that the unexpected dimming of the supergiant star Betelgeuse was most likely caused by an immense amount of hot material ejected into space, forming a dust cloud that blocked starlight coming from Betelgeuse’s surface.
Betelgeuse is an aging, red supergiant star that has swelled in size as a result of complex, evolving changes in the nuclear fusion processes in its core. The star is so large that if it replaced the Sun at the centre of our Solar System, its outer surface would extend past the orbit of Jupiter. The unprecedented phenomenon of Betelgeuse’s great dimming, eventually noticeable to even the naked eye, began in October 2019. By mid-February 2020, the brightness of this monster star had dropped by more than a factor of three.
This sudden dimming has mystified astronomers, who sought to develop theories to account for the abrupt change. Thanks to new Hubble observations, a team of researchers now suggest that a dust cloud formed when superhot plasma was unleashed from an upwelling of a large convection cell on the star’s surface and passed through the hot atmosphere to the colder outer layers, where it cooled and formed dust. The resulting cloud blocked light from about a quarter of the star’s surface, beginning in late 2019. By April 2020, the star had returned to its normal brightness.
Several months of Hubble’s ultraviolet-light spectroscopic observations of Betelgeuse, beginning in January 2019, produced an insightful timeline leading up to the star’s dimming. These observations provided important new clues to the mechanism behind the dimming. Hubble saw dense, heated material moving through the star’s atmosphere in September, October, and November 2019. Then, in December, several ground-based telescopes observed the star decreasing in brightness in its southern hemisphere.
“With Hubble, we see the material as it left the star’s visible surface and moved out through the atmosphere, before the dust formed that caused the star appear to dim,” said lead researcher Andrea Dupree, associate director of The Center for Astrophysics, Harvard & Smithsonian. “We could see the effect of a dense, hot region in the southeast part of the star moving outward.”
“This material was two to four times more luminous than the star’s normal brightness,” she continued. “And then, about a month later, the southern hemisphere of Betelgeuse dimmed conspicuously as the star grew fainter. We think it is possible that a dark cloud resulted from the outflow that Hubble detected. Only Hubble gives us this evidence of what led up to the dimming.”
The team began using Hubble early last year to analyse the massive star. Their observations are part of a three-year Hubble study to monitor variations in the star’s outer atmosphere. The telescope’s sensitivity to ultraviolet light allowed researchers to probe the layers above the star’s surface, which are so hot that they emit mostly in the ultraviolet region of the spectrum and are not seen in visible light. These layers are heated partly by the star’s turbulent convection cells bubbling up to the surface.
“Spatially resolving a stellar surface is only possible in favourable cases and only with the best available equipment,” said Klaus Strassmeier of the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany. “In that respect, Betelgeuse and Hubble are made for each other.”
Hubble spectra, taken in early and late 2019 and in 2020, probed the star’s outer atmosphere by measuring spectral lines of ionised magnesium. From September to November 2019, the researchers measured material passing from the star’s surface into its outer atmosphere. This hot, dense material continued to travel beyond Betelgeuse’s visible surface, reaching millions of kilometres from the star. At that distance, the material cooled down enough to form dust, the researchers said.
This interpretation is consistent with Hubble ultraviolet-light observations in February 2020, which showed that the behaviour of the star’s outer atmosphere returned to normal, even though in visible light it was still dimming.
Although Dupree does not know the cause of the outburst, she thinks it was aided by the star’s pulsation cycle, which continued normally though the event, as recorded by visible-light observations. Strassmeier used an automated telescope of the Leibniz Institute for Astrophysics called STELLar Activity (STELLA) to measure changes in the velocity of the gas on the star’s surface as it rose and fell during the pulsation cycle. The star was expanding in its cycle at the same time as the convective cell was upwelling. The pulsation rippling outward from Betelgeuse may have helped propel the outflowing plasma through the atmosphere.
The red supergiant is destined to end its life in a supernova blast and some astronomers think the sudden dimming may be a pre-supernova event. The star is relatively nearby, about 725 light-years away, so the dimming event would have happened around the year 1300, as its light is just reaching Earth now.
Dupree and her collaborators will get another chance to observe the star with Hubble in late August or early September.
See the original press release with links at https://www.spacetelescope.org/news/heic2014/
-- The press release was passed on by Karen Pollard.
8. Saturn-mass Exoplanet Found by Radio Astronomers
An international team of astronomers have discovered a Saturn-like planet orbiting a small, cool star by detecting the “wobble” in the star’s motion caused by the gravitational pull of the planet. This is the first time that this technique is successfully employed with observations obtained at radio wavelengths. For their observations, the researchers used a network of radio antennas that are linked together to form a continent-size radio telescope. The discovery was possible thanks to the extremely high precision measurements of the star’s position that can only be achieved with such a radio telescope network.
One of the things that makes this detection exciting is that the planet, called TVLM 513b, has a similar mass to Saturn and an orbit analogous to that of Mercury in our solar system. Only a handful of extrasolar planets with characteristics similar to TVLM 513b have been discovered so far around small, cool stars -- known as ultracool dwarfs. Other planet search techniques have difficulties studying these dwarfs, mainly due to the faintness of the objects, which makes radio observations a very powerful and complementary tool to uncover many more new planets.
The star, TVLM 513-46546, is a cool dwarf with less than a tenth the mass of our Sun in the constellation Boötes (The Herdsman). It is 35 light-years from Earth.
This is the first discovery of an extrasolar planet with a radio telescope using a technique that requires extremely precise measurements of a star’s position in the sky, and only the second planet discovery for that technique and for radio telescopes.
The technique has long been known, but has proven difficult to use. It involves tracking the star’s actual motion in space, then detecting a minuscule “wobble” in that motion caused by the gravitational effect of the planet. The star and the planet orbit a location called the barycentre, the centre of mass for both combined. The planet is revealed indirectly if the barycentre is far enough from the star’s centre to cause a wobble detectable by a telescope.
This technique, called the astrometric technique, is expected to be particularly good for detecting Jupiter-like planets in orbits distant from the star. This is because when a massive planet orbits a star, the wobble produced in the star increases with a larger separation between the planet and the star, and at a given distance from the star, the more massive the planet, the larger the wobble produced.
Starting in June of 2018 and continuing for a year and a half, the astronomers tracked the star. In addition, they used data from nine previous VLBA observations of the star between March 2010 and August 2011. Extensive analysis of the data from those time periods revealed a tell-tale wobble in the star’s motion indicating the presence of a planet comparable in mass to Saturn, orbiting the star once every 221 days. This planet is closer to the star than Mercury is to the Sun.
Small, cool stars like TVLM 513-46546 are the most numerous stellar type in our Milky Way Galaxy, and many of them have been found to have smaller planets, comparable to Earth and Mars.
“Giant planets, like Jupiter and Saturn, are expected to be rare around small stars like this one, and the astrometric technique is best at finding Jupiter-like planets in wide orbits, so we were surprised to find a lower mass, Saturn-like planet in a relatively compact orbit. We expected to find a more massive planet, similar to Jupiter, in a wider orbit,” said Salvador Curiel, of the National Autonomous University of Mexico. “Detecting the orbital motions of this sub-Jupiter mass planetary companion in such a compact orbit was a great challenge,” he added.
More than 4,300 planets have been discovered orbiting stars other than the Sun, but the planet around TVLM 513-46546 is only the second to be found using the astrometric technique. Another, very successful method, called the radial velocity technique, also relies on the gravitational effect of the planet upon the star. That technique detects the slight acceleration of the star, either toward or away from Earth, caused by the star’s motion around the barycenter. The astrometric method complements the radial velocity method which is more sensitive to planets orbiting in close orbits. The astrometric method is more sensitive to massive planets in orbits further away from the star.
A third technique, called the transit method, also very successful, detects the slight dimming of the star’s light when a planet passes in front of it, as seen from Earth.
“The VLBA, with antennas separated by as much as 5,000 miles [8000 km], provided us with the great resolving power and extremely high precision needed for this discovery,” said Amy Mioduszewski, of the U.S. National Radio Astronomy Observatory. “In addition, improvements that have been made to the VLBA’s sensitivity gave us the data quality that made it possible to do this work now,” she added.
See the original press release at
https://www.mpifr-bonn.mpg.de/pressreleases/2020/7
-- Forwarded by Karen Pollard.
9. Cool Nearby Brown Dwarfs Discovered
How complete is our census of the Sun’s closest neighbours? Astronomers and a team of data-sleuthing volunteers participating in Backyard Worlds: Planet 9, a citizen science project, have discovered roughly 100 cool worlds near the Sun -- objects more massive than planets but lighter than stars, known as brown dwarfs.
With the help of W. M. Keck Observatory on Maunakea in Hawaii, the research team found several of these newly discovered worlds are among the very coolest known, with a few approaching the temperature of Earth -- cool enough to harbour water clouds. The study was published in the August 20, 2020, issue of The Astrophysical Journal and is available in preprint format on arXiv.org.
Discovering and characterizing astronomical objects near the Sun is fundamental to our understanding of our place in, and the history of, the universe. Yet astronomers are still unearthing new residents of the solar neighbourhood. The new Backyard Worlds discovery bridges a previously empty gap in the range of low-temperature brown dwarfs, identifying a long-sought missing link within the brown dwarf population.
“These cool worlds offer the opportunity for new insights into the formation and atmospheres of planets beyond the solar system,” said lead author Aaron Meisner from the National Science Foundation’s NOIRLab. “This collection of cool brown dwarfs also allows us to accurately estimate the number of free-floating worlds roaming interstellar space near the Sun.
To identify several of the faintest and coolest of the newly discovered brown dwarfs, UC San Diego’s Professor of Physics Adam Burgasser and researchers from the Cool Star Lab used Keck Observatory’s sensitive Near-Infrared Echellette Spectrometer, or NIRES, instrument.
“We used the NIRES spectra to measure the temperature and gases present in their atmospheres. Each spectrum is essentially a fingerprint that allows us to distinguish a cool brown dwarf from other kinds of stars,” said Burgasser, a co-author of the study. Follow-up observations using NASA’s Spitzer Space Telescope, Mont Mégantic Observatory, and Las Campanas Observatory also contributed to the brown dwarf temperature estimates.
Brown dwarfs lie somewhere between the most massive planets and the smallest stars. Lacking the mass needed to sustain nuclear reactions in their core, brown dwarfs are sometimes referred to as “failed stars.” Their low mass, low temperature, and lack of internal nuclear reactions make them extremely faint -- and therefore extremely difficult to detect. Because of this, when searching for the very coolest brown dwarfs, astronomers can only hope to detect such objects relatively close to the Sun.
To help find our Sun’s coldest, nearest neighbours, astronomers with the Backyard Worlds project turned to a worldwide network of more than 100,000 citizen scientists. These volunteers diligently inspect trillions of pixels of telescope images to identify the subtle movements of nearby brown dwarfs and planets. Despite the advances of machine learning and supercomputers, there’s still no substitute for the human eye when it comes to finding faint, moving objects.
Backyard Worlds volunteers have already discovered more than 1,500 stars and brown dwarfs near the Sun; this new discovery represents about 100 of the coldest in that sample. Meisner says this is a record for any citizen science program, and 20 of the citizen scientists are listed as co-authors of the study.
The availability of decades of astronomical catalogues through NOIRLab’s Astro Data Lab helped make the discoveries possible. “The technical burden of downloading billion-object astronomical catalogues is typically insurmountable for individual investigators -- including most professional astronomers,” said Meisner. “Thankfully, the Astro Data Lab’s open and accessible web portal allowed Backyard Worlds citizen scientists to easily query massive catalogues for brown dwarf candidates.”
Data sets from NASA’s WISE satellite as well as archival observations from telescopes at Cerro Tololo Inter-American Observatory and Kitt Peak National Observatory were also key to these brown dwarf discoveries.
“It’s exciting these could be spotted first by a citizen scientist,” said Meisner. “The Backyard Worlds discoveries show that members of the public can play an important role in reshaping our scientific understanding of our solar neighbourhood.”
For the original text & graphics see:
https://keckobservatory.org//cool-brown-dwarfs
-- From a W. M. Keck Observatory press release forwarded by Karen Pollard.
10. Tiny asteroid Whizzes Past
The ‘Tunguska Event’ of 1908 happened when an object about 50 metres across exploded above the Siberian taiga – but smaller cosmic rocks shoot close by Earth fairly frequently. On July 26 a tiny asteroid less than five metres in size was discovered by astronomers in Arizona, then tracked from Mt John Observatory in New Zealand and by observers in Croatia and France. The object passed 50,000 km from Earth's centre on the afternoon of the 28th, NZ time.
This asteroid is called 2020 OY4. With automated spotting of asteroids with robotic telescopes there are thousands of ‘discoveries’ every night nowadays – most of which are repeat detections of objects that are already in our data banks. Many, though, are new: this asteroid 2020 OY4 could not have been found previously because it is too small and so very faint, beyond the grasp of our telescopes unless it happens to pass close by Earth. Which is what it did.
It was found late on Sunday July 26 (NZST) when a telescope at Mt Lemmon near Tucson, Arizona, picked it up. The University of Arizona team then obtained further observations with another telescope at the same site.
Within four hours of its discovery, and with daylight approaching in the western United States, observatories further west (into night-time) were needed to take over the tracking.
This was done by Pam Kilmartin and Alan Gilmore of Mt John Observatory (part of the University of Canterbury), at Lake Tekapo. The Mt John observations showed that the slow-moving object had a large parallax so was close by, about 1.7 million km away, and headed straight for Earth. As the Earth turned, the two telescopes in Europe were able to obtain more positions for the asteroid, enabling mathematicians who work on orbital dynamics to determine that it would miss our planet by a safe distance. It passed to the north of NZ, across the centre of Australia, and at 17:31 (5:31 pm) NZST on Tuesday 28th July it made its closest approach to Earth, over southern Africa. No further observations were feasible because it passed into the daytime sky.
It seems quite remarkable that such a tiny rock – estimated to be between two and five metres in dimension – could be discovered and then within a day or so astronomers can say for sure that it will miss our planet, even giving the miss distance to within just 50 km, a minute length on any cosmic scale.
If you wish to know more about this particular asteroid, see
https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2020%20OY4
the NASA-JPL Near-Earth Object web page about it, or go to
https://newton.spacedys.com/neodys/index.php?pc=1.1.0&n=2020OY4
at the Near-Earth Objects Dynamics site at the University of Pisa in Italy. The little asteroid goes out to about the distance of Mars away from the Sun, then dips inwards to skim past the orbit of Venus, passing Earth on the way.
Tiny rocks like this one are not actually anything to worry about. Something this small would explode high in the atmosphere, although it would be something to behold. If had been on a collision course with Earth, it would have entered the atmosphere at about 60,000 kilometres per hour, 17 km/s, and released energy equivalent to about three kilotonnes of TNT (one-quarter the Hiroshima nuclear bomb). But apart from shaking people up a little such an explosion occurring far above the height that jumbo jets fly would have little effect on us far below. The last time that an asteroid caused real damage was in February 2013, when a bigger asteroid (about 15-20 metres in size) blew up over Chelyabinsk in Russia, putting over a thousand people into hospital. And near-misses (near-hits?) by relatively small asteroids occur frequently; see
https://cneos.jpl.nasa.gov/ca/ for a list.
It’s bigger asteroids (and comets) that we need to take more seriously.
An example is 2020 NK1. You can tell from that designation that it has just been discovered in the past few weeks (i.e. the ‘N’ tells you: between July 1-15). And this is a big one, estimated to be about half-a-kilometre wide. The initial orbit indicated that there were seven times between the years 2091 and 2101 that this humdinger would pass close by Earth, with a collision being possible. It’s the first asteroid in a while to have a non-zero assignation on the Torino Scale for asteroid impact risk. Fortunately follow-up radar ranging by the Arecibo radio telescope greatly improved the orbital data and showed that 2020 NK1 isn't a danger for the foreseeable.
-- Adapted from Duncan Steel's blog post. See the original with addenda, images and links at
https://sciblogs.co.nz/out-of-space/2020/07/28/tiny-asteroid-whizzing-past-earth-today/
11. Arecibo Radio Telescope Damaged
One of the largest radio telescopes in the world, used by NASA as part of its planetary defence program, is out of service indefinitely after suffering damage from a broken cable.
The University of Central Florida, part of the consortium that operates the Arecibo Observatory in Puerto Rico, said a cable used to help support a platform above the main reflector dish snapped in the early morning hours Aug. 10. The cable created a gash about 30 meters long in the dish, and damaged panels in a receiver called the Gregorian Dome mounted on that platform.
Observatory officials said in an Aug. 11 statement that they did not know what caused the cable to break. “We have a team of experts assessing the situation,” Francisco Cordova, director of the observatory, said, with a goal of “restoring the facility to full operations as soon as possible.” He did not estimate how long the repairs will take or how much they will cost.
Arecibo was built in the early 1960s as the largest single-dish radio telescope in the world, with a diameter of 305 meters. It remained the largest in the world for decades, until China completed the Five Hundred Meter Aperture Spherical Telescope, or FAST, in 2016.
The observatory has, in recent years, been battered by both natural catastrophes and financial uncertainty. Earthquakes and hurricanes have damaged the telescope, including the powerful Hurricane Maria in 2017. Some repairs from that hurricane are still in progress.
Efforts in recent years by the National Science Foundation (NSF), which funds the majority of Arecibo’s operations, to divest some of its astronomical facilities also raised questions about Arecibo’s long-term future. NSF selected a group led by the University of Central Florida, with Universidad Ana G. Méndez and Yang Enterprises Inc., to run the telescope in 2018.
Part of Arecibo’s funding comes from NASA, which uses a planetary radar system at the observatory to track and characterize near Earth objects as part of the agency’s planetary defence program. While Arecibo isn’t used to discover asteroids, that radar system can refine the orbits of asteroids and measure their shapes.
One example is asteroid 2020 NK1, discovered by a telescope in Hawaii in early July and whose initial orbit showed it posed an impact risk to the Earth late this century. Observations by Arecibo’s planetary radar in late July ruled out any impact threat, while also measuring the size and shape of the asteroid.
-- See the original article at
https://spacenews.com/arecibo-radio-observatory-damaged/
The link passed along by Duncan Steel.
Karen Pollard also passed along a link:
https://www.sciencemag.org/news/2020/08/arecibo-radio-telescope-goes-dark-after-snapped-cable-shreds-dish
12. Quote
"…the internet has simultaneously enabled two opposing influences on belief: On the one hand, it has reduced intellectual isolation by making it more difficult for people to remain ignorant of the diversity of opinion on any given subject. But it has also allowed bad ideas to flourish -- as anyone with a computer and too much time on his hands can broadcast his point of view and, often enough, find an audience. So while knowledge is increasingly open-source, ignorance is, too. -- Sam Harris in "The Moral Landscape", p. 123.
Alan Gilmore Phone: 03 680 6817
P.O. Box 57 alan.gilmore@canterbury.ac.nz
Lake Tekapo 7945
New Zealand
Hi,
Please find the latest Keeping in Touch (#37) below. It is about the cancellation of the 2020 RASNZ physical conference in Wellington (it was going to be on during Labour Weekend). For some reason I can't attach/send the usual PDF or Word version so am embedding it in the text below.
Please pass on to astronomy friends, local society members, etc.
Many thanks
John Drummond
RASNZ Executive Secretary
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KEEPING IN TOUCH #37. Thu 20th August 2020
PLEASE pass on to all your local astronomical society members
Hi and welcome to ‘Keeping in Touch’ #37. This issue is mainly about the cancellation of the 2020 RASNZ conference in Wellington...
1. THE PHYSICAL RASNZ CONFERENCE IN WELLINGTON CANCELLED DUE TO COVID-19 UNCERTAINTIES –
These two letters, from RASNZ President Dr Nick Rattenbury –
Thursday 20 August 2020
Dear RASNZ Member and 2020 RASNZ Conference Registrants,
It is with great regret that we have to inform you that the 2020 RASNZ Conference, AGM and associated meetings will not go ahead in person as planned in October. This decision was driven largely by the recent return to heightened travel restrictions and isolation measures in response to the re-emergence of Covid-19.
Our Society has a responsibility to manage its affairs in light of current Government policy and prevailing health advice regarding novel coronavirus covid-19. We do not want to expose our Members or guests to any unnecessary risk of infection or financial or other impact in the event of any last-minute cancellation due to the fluctuating nature of alert levels.
We do aim however to hold the AGM on-line. We hope to include other online events including networking opportunities for our younger members. We will be in touch in due course with details once they are finalised.
There will be no cost for anyone wishing to attend any online event organised by RASNZ over the Labour Weekend. For those of you who have already paid your registration fees, your options are:
1. Take no action, and your registration will remain on record for the next in-person Conference, or
2. Request a full refund, by emailing the conference organisers and providing your bank account details.
Until then, please take care of yourself and yours. If you have any questions, please do not hesitate to contact me at president@rasnz.org.nz
We look forward to seeing you at our next in-person conference.
Yours faithfully, Nicholas Rattenbury, President, RASNZ (My – John D’s formatting to fit everything on one page)
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Dear RASNZ 2020 Conference Presenters,
Thank you for your offer to give an oral or poster presentation at the 2020 RASNZ Conference, Wellington. It is with great regret that we have to inform you that the 2020 RASNZ Conference, AGM and associated meetings will not go ahead in person as planned in October. This decision was driven largely by the recent return to heightened travel restrictions and isolation measures in response to the reemergence of COVID-19.
Our Society has a responsibility to manage its affairs in light of current Government policy and prevailing health advice regarding novel coronavirus COVID-19. We do not want to expose our Members or guests to any unnecessary risk of infection or financial or other impact in the event of any last minute cancellation due to the fluctuating nature of alert levels.
We do aim however to hold the AGM on-line. We hope to include other online events such as networking opportunities for our younger members. We will be in touch in due course with details once they are finalised. We hope that you will take the opportunity to share your expertise with Society members in one or more of these online activities.
If you have any questions, please do not hesitate to contact me at president@rasnz.org.nz
Yours faithfully, Nicholas Rattenbury, President, RASNZ president@rasnz.org.nz (My – John D’s formatting to fit everything on one page)
2. 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
Remember to visit our Affiliated Societies page –
http://rasnz.org.nz/rasnz/affiliated-societies-details
Regards, John Drummond, FRASNZ, Executive Secretary
Email: kiwiastronomer@gmail.com . Phone: 0275 609 287
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June Celestial Calendar by Dave Mitsky
August Celestial Calendar by Dave Mitsky
All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)
8/1 Mercury is at the ascending node through the ecliptic plane at 12:00; Venus is at its southernmost latitude from the ecliptic plane (-3.4 degrees) at 15:00
8/2 The Moon is 1.5 degrees south of Jupiter at 0:00; Mercury is 6.6 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 1:00; the Moon is 1.1 degrees south of Pluto, with an occultation taking place in most of eastern Antarctica, at 6:00; Uranus is at western quadrature at 11:00; the Moon is 2.3 degrees southeast of Saturn at 14:00
8/3 Mars is at perihelion (1.3814 astronomical units from the Sun) at 9:00; Full Moon (known as the Fruit, Grain, Green Corn, or Sturgeon Moon) occurs at 15:59
8/5 The astronomical cross-quarter day known as Lammas or Lughnasadh, the midpoint between the summer solstice and the autumnal equinox, occurs today
8/6 Mercury is at perihelion (0.3075 astronomical units from the Sun) at 4:00; the Moon is 4.0 degrees southeast of Neptune at 19:00
8/9 Mercury is 0.1 degrees southeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 1:00; the Moon is 0.8 degrees southeast of Mars, with an occultation occurring in the Ascension Islands, southeastern South America, and most of western Antarctica, at 8:00; the Moon is at apogee, subtending 29' 32" at a distance of 404,659 kilometers (251,443 miles) at 14:00
8/10 The Sun enters the constellation of Leo, at longitude 138.2 degrees on the ecliptic, at 9:00; Venus is 4.4 degrees south of the bright open cluster M35 in Gemini at 11:00
8/11 The Moon is 3.3 degrees southeast of Uranus at 0:00; Last Quarter Moon occurs at 16:45
8/12 The Curtiss Cross, an X-shaped clair-obscur illumination effect located between the craters Parry and Gambart, is predicted to be visible at 12:56; the peak of the Perseid meteor shower (a zenithal hourly rate of 90 or more per hour) occurs at 13:00; the Moon is 6.4 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 16:00; Venus is at dichotomy (50% illumination) at 21:00
8/13 Venus is at greatest western elongation (45.8 degrees) at 0:00; the Moon is 3.9 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 10:00
8/14 The Moon is at the ascending node (longitude 87.8 degrees) at 19:00
8/15 A double Galilean shadow transit (Io's shadow follows Ganymede's) begins at 4:08; the Moon is 0.6 degrees southeast of the bright open cluster M35 at 5:00; the Moon is 4.0 degrees north of Venus at 14:00; Uranus is stationary, with retrograde (western) motion to begin, at 17:00
8/16 Mercury is at its northernmost latitude from the ecliptic plane (7.0 degrees) at 9:00; the Moon is 8.1 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 15:00; the Moon is 4.5 degrees south of the first-magnitude star Pollux at 20:00
8/17 Mercury is in superior conjunction with the Sun (1.354 astronomical units from Earth, latitude 7.0 degrees) at 15:00; the Moon is 2.0 degrees north-northeast of the bright open cluster M44 at 19:00
8/19 New Moon (lunation 1208) occurs at 2:42; the Moon is 2.7 degrees north-northeast of Mercury at 6:00; the Moon, Mercury, and the first-magnitude star Regulus (Alpha Leonis) lie within a circle with a diameter of 4.0 degrees at 8:00; the Moon is 4.1 degrees north-northeast of Regulus at 9:00
8/20 Mercury is 1.3 degrees north-northeast of Regulus at 4:00
8/21 The Moon is at perigee, subtending 32' 52'' from a distance of 363,513 kilometers (225,876 miles), at 11:00; the Sun's longitude is 150 degrees at 16:00
8/22 A double Galilean shadow transit (Ganymede's shadow follows Io's) begins at 6:32
8/23 The Moon is 6.6 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 2:00; Mars and Neptune are at heliocentric conjunction (longitude 349.4 degrees) at 22:00
8/25 First Quarter Moon occurs at 17:58
8/26 The Lunar X, also known as the Werner or Purbach Cross, an X-shaped clair-obscur illumination effect involving various ridges and crater rims located between the craters La Caille, Blanchinus, and Purbach, is predicted to be fully formed at 1:06; the Moon is 6.0 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 8:00
8/27 The Moon is at the descending node (longitude 266.8 degrees) at 12:00
8/28 The dwarf planet/asteroid 1 Ceres is at opposition at 12:00
8/29 The Moon is 1.4 degrees south of Jupiter at 2:00; the Moon is 1.2 degrees south of Pluto, with an occultation taking place in most of western Antarctica and Queen Maude Land, at 11:00; the Moon is 2.2 degrees southeast of Saturn at 18:00
8/31 Venus is 8.6 degrees south of Pollux at 21:00
John Flamsteed, Christian Mayer, Pierre François André Méchain, Maria Mitchell, and Otto Struve were born this month.
The gibbous phase of Mars was first observed by Francesco Fontana on August 24, 1638. Abraham Ihle discovered the globular cluster M22 on August 26, 1665. Nicolas Sarabat discovered Comet C/1729 P1 (Sarabat) on August 1, 1729. Caroline Herschel discovered Comet C/1786 P1 (Herschel) on August 1, 1786. The Saturnian satellite Enceladus was discovered by William Herschel on August 28, 1789. Dominique Dumouchel was the first person to observe the return of Comet 1P/Halley on August 5, 1835. John Russell Hind discovered asteroid 7 Iris on August 13, 1847. Asaph Hall discovered Deimos on August 11, 1877 and Phobos on August 17, 1877. The first extragalactic supernova, S Andromedae, was discovered by Ernst Hartwig on August 20, 1885. David Jewitt and Jane Luu discovered the trans-Neptunian object (15760) 1992 QB1 on August 30, 1992. The Jovian satellite 2002 Laomedeia was discovered by Matthew Holman on August 13th, 2002.
The peak of the Perseid meteor shower takes place on the night of August 11th/August 12th and is compromised by moonlight from an almost Last Quarter Moon. The periodic comet 109P/Swift-Tuttle is the source of Perseid meteors. The shower’s radiant lies just to the southeast of the Double Cluster (NGC 869 and NGC 884). For more on this year’s Perseids, see page 50 of the August 2020 issue of Sky & Telescope or click on https://earthsky.org/astronomy-essentials/everything-you-need-to-know-perseid-meteor-shower and https://earthsky.org/?p=165416
Information on passes of the ISS, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/
The Moon is 11.1 days old, is illuminated 91.3%, subtends 31.6 arc minutes, and is located in Sagittarius on August 1st at 0:00 UT. The Moon is at its greatest northern declination on August 16th (+24.1 degrees) and its greatest southern declination on August 1st (-24.0 degrees) and on August 29th (-24.1 degrees). Longitudinal libration is at a maximum of +4.9 degrees on August 2nd and +5.9 degrees on August 28th and a minimum of -6.3 degrees on August 16th. Latitudinal libration is at a maximum of +6.7 degrees on August 7th and a minimum of -6.6 degrees on August 21st. Favorable librations for the following lunar features occur on the indicated dates: Mare Marginis on August 1st, Mare Orientale on August 16th, Mare Australe on August 24th, and Mare Smythii on August 27th. An article on observing lunar maria during librations taking place this month appears on pages 52 and 53 of the August 2020 issue of Sky & Telescope. The Moon is at apogee (at a distance 63.45 Earth-radii) on August 9th and at perigee (at a distance of 57:00 Earth-radii) on August 21st. New Moon (i.e., the dark of the Moon) occurs on August 19th. A young waxing crescent Moon passes a bit more than one degree from the binary star Porrima (Gamma Virginis) on August 21st. The Moon occults Pluto on August 2nd and August 29th and Mars on August 9th from certain parts of the world. Browse http://www.lunar-occultations.com/iota/bstar/bstar.htm for information on upcoming lunar occultations. Visit https://saberdoesthestars.wordpress.com/2011/07/05/saber-does-the-stars/ 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/maria.html?fbclid=IwAR0L-CYMauWi6Hhc09wUanCBQeDKNEw3gVJBHRwr0QEcodMJtNWK1OLMxYk for a list of lunar maria and https://upload.wikimedia.org/wikipedia/commons/thumb/3/36/Moon_names.jpg/600px-Moon_names.jpg?fbclid=IwAR1zUN--tW5jgxQPVOfp_6PpRtvXjprmsdrR531bAAjotCZImsof8HUNAKI for a simple map of the Moon showing the most prominent maria. See https://svs.gsfc.nasa.gov/4768 for a lunar phase and libration calculator and https://svs.gsfc.nasa.gov/4768 for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap. Click on https://www.calendar-12.com/moon_calendar/2020/august 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 Cancer on August 1st. It enters the constellation of Leo on August 10th and achieves an ecliptic longitude of 150 degrees on August 21st.
Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on August 1: Mercury (magnitude -0.9, 6.1", 70% illuminated, 1.10 a.u., Gemini), Venus (magnitude -4.5, 27.2", 43% illuminated, 0.61 a.u., Taurus), Mars (magnitude -1.1, 14.6", 86% illuminated, 0.64 a.u., Pisces), Jupiter (magnitude -2.7, 47.2", 100% illuminated, 4.18 a.u., Sagittarius), Saturn (magnitude +0.1, 18.4", 100% illuminated, 9.01 a.u., Sagittarius), Uranus (magnitude +5.7, 3.6", 100% illuminated, 19.54 a.u. on August 16th, Aries), Neptune (magnitude +7.8, 2.4", 100% illuminated, 29.02 a.u. on August 16th, Aquarius), and Pluto (magnitude +14.3, 0.1", 100% illuminated, 33.11 a.u. on August 16th, Sagittarius).
Mercury lies very low in the eastern sky at dawn. It's at perihelion on August 6th and at its greatest heliocentric latitude north on August 16th. The speediest planet is in inferior conjunction on August 17th. It will become visible again in the evening sky near the end of the month.
During August, Venus dips in brightness from magnitude -4.5 to magnitude -4.3 and in angular size from 27.2 arc seconds to 21.7 arc seconds, while it grows in illumination from 43% to 59%. Venus and the third-magnitude star Zeta Tauri are less than two degrees apart in early August. Venus is at its greatest heliocentric latitude south on August 2nd. It reaches greatest western elongation on August 12th but doesn't attain its highest sunrise altitude of approximately 40 degrees until month's end. The waning crescent Moon passes four degrees to the north of the planet on August 15th. Venus travels eastward through Taurus and northern Orion and enters southern Gemini near the end of August.
Mars rises two hours after sunset by the end of August. The Red Planet brightens from magnitude -1.1 to magnitude -1.8 and increases in angular diameter from 14.6 arc seconds to 18.7 arc seconds. Mars is at perihelion on August 3rd. An impressive lunar conjunction takes place on August 9th, when the waning gibbous Moon passes about one degree to the south of Mars.
Jupiter decreases slightly in brightness from magnitude -2.7 to magnitude -2.6 and diminishes in apparent size from 47.2 to 44.4 arc seconds during August. Jupiter remains approximately eight degrees west of Saturn this month. The distance slowly increases as both gas giants retrograde. The Moon passes two degrees to the south of Jupiter on August 1st/August 2nd and again on August 28th/August 29th. Double Galilean satellite shadow transits occur on August 14th and August 22nd. Information on Great Red Spot transit times and Galilean satellite events is available on pages 50 and 51 of the August 2020 issue of Sky & Telescope and online at http://www.skyandtelescope.com/observing/interactive-sky-watching-tools/ and https://www.projectpluto.com/jevent.htm
Saturn shrinks from 18.4 to 18.0 arc seconds in angular diameter and drops in brightness from magnitude +0.1 to +0.3 this month. Its rings are inclined by more than 22 degrees with respect to the Earth and span 42 arc seconds. On August 2nd and August 29th, the Moon passes two degrees to the south of Saturn. For information on Saturn’s satellites, browse http://www.skyandtelescope.com/observing/interactive-sky-watching-tools/
Uranus is located in southern Aries. It transits the meridian around sunrise. The waning gibbous Moon passes three degrees southeast of Uranus on the night of August 10th/August 11th. Uranus reaches its first stationary point on August 15th. On that date, it will be at its highest declination (almost +15 degrees) since the early 1960s. Visit http://www.nakedeyeplanets.com/uranus.htm for a finder chart.
Neptune can be found in eastern Aquarius. The waning gibbous Moon passes four degrees southeast of Neptune on August 6th. Mars and Neptune are at heliocentric conjunction on August 23rd. Browse http://www.nakedeyeplanets.com/neptune.htm for a finder chart.
Finder charts for Uranus and Neptune are also available at https://skyandtelescope.org/wp-content/uploads/UranusNeptune2020_BW_WebFinder.pdf and an article on observing the ice giants is posted at https://skyandtelescope.org/observing/ice-giants-neptune-and-uranus/
The dwarf planet Pluto is occulted by the Moon from some parts of the world on August 2nd and August 29th. Finder charts can be found at pages 48 and 49 of the July 2020 issue of Sky & Telescope and on page 243 of the RASC Observer’s Handbook 2020.
For more on the planets and how to locate them, see http://www.nakedeyeplanets.com/
Comet C/2020 F3 (NEOWISE) put on a fine show last month, reaching naked-eye visibility from reasonably dark sites and producing rather long ion and dust tails. It reached perihelion on July 3rd and made its closest approach to the Earth on July 23rd. Comet NEOWISE will continue to dim as it moves increasingly farther from the Earth. See https://spaceweathergallery.com/index.php?title=neowise for a photo gallery of the comet. For further information on comets visible this month, browse http://cometchasing.skyhound.com/ and http://www.aerith.net/comet/future-n.html
Asteroid 1 Ceres (magnitude +7.7), which is also classified as a dwarf planet, reaches opposition in southern Aquarius on August 28th. An article on the largest of the asteroids appears on pages 50 and 51 of the August 2020 issue of Sky & Telescope. Other asteroids brighter than magnitude +11.0 reaching opposition include 44 Nysa (magnitude +10.6), 138 Tolosa (magnitude +10.8), and 20 Massalia (magnitude +9.7). For information on asteroid occultations taking place this month, see http://www.asteroidoccultation.com/2018_08_si.htm
A wealth of current information on solar system celestial bodies is posted at http://nineplanets.org/ and http://www.curtrenz.com/astronomy.html
Information on the celestial events transpiring each week can be found at https://stardate.org/nightsky and http://astronomy.com/skythisweek and http://www.skyandtelescope.com/observing/sky-at-a-glance/
Free star maps for this month can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescope.com/content.jsp?pageName=Monthly-Star-Chart
Data on current supernovae can be found at http://www.rochesterastronomy.org/snimages/
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/turnleft/seasonal_skies_july-september
Telrad finder charts for the Messier Catalog are posted at http://www.custerobservatory.org/docs/messier2.pdf
Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynights.com/topic/358295-how-to-locate-some-of-the-major-messier-galaxies-and-helpful-advice-for-novice-amateur-astronomers/
Freeware sky atlases can be downloaded at http://www.deepskywatch.com/files/deepsky-atlas/Deep-Sky-Hunter-atlas-full.pdf and http://astro.mxd120.com/free-star-atlases
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 two excellent 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://dso-browser.com/ and http://tonightssky.com/MainPage.php
Sixty binary and multiple stars for August: 5 Aquilae, Struve 2404, 11 Aquilae, Struve 2426, 15 Aquilae, Struve 2449, 23 Aquilae, Struve 2532, Pi Aquilae, 57 Aquilae (Aquila); Beta Cygni (Albireo), 16 Cygni, Delta Cygni, 17 Cygni (Cygnus); 41 & 40 Draconis, 39 Draconis, Struve 2348, Sigma Draconis, Struve 2573, Epsilon Draconis (Draco); 95 Herculis, 100 Herculis, Struve 2289, Struve 2411 (Hercules); Struve 2349, Struve 2372, Epsilon-1 & Epsilon-2 Lyrae (the Double-Double), Zeta-2 Lyrae, Beta Lyrae, Otto Struve 525, Struve 2470 & Struve 2474 (the Other Double-Double) (Lyra); 67 Ophiuchi, 69 Ophiuchi, 70 Ophiuchi, Struve 2276, 74 Ophiuchi (Ophiuchus); Mu Sagittarii, Eta Sagittarii, 21 Sagittarii, Zeta Sagittarii, H N 119, 52 Sagittarii, 54 Sagittarii (Sagittarius); Struve 2306, Delta Scuti, Struve 2373 (Scutum); Struve 2296, Struve 2303, 59 Serpentis, Theta Serpentis (Serpens Cauda); Struve 2445, Struve 2455, Struve 2457, 4 Vupeculae, Struve 2521, Struve 2523, Struve 2540, Struve 2586, Otto Struve 388, Struve 2599 (Vulpecula)
Notable carbon star for August: V Aquilae
Eighty deep-sky objects for August: B139, B142, B143, NGC 6709, NGC 6738, NGC 6741, NGC 6751, NGC 6755, NGC 6772, NGC 6778, NGC 6781, NGC 6804, PK64+5.1 (Aquila); NGC 6819, NGC 6826, NGC 6834, (Cygnus); NGC 6643, NGC 6742 (Draco); DoDz 9 (Hercules); M56, M57, NGC 6703, NGC 6791, Ste1 (Lyra); NGC 6572, NGC 6633 (Ophiuchus); H20, M71 (Sagitta); B86, B87, B90, B92, B93, M8, M17, M18, M20, M21, M22, M23, M24, M25, M28, M54, M55, M69, M70, M75, NGC 6520, NGC 6544, NGC 6546, NGC 6553, NGC 6565, NGC 6603, NGC 6818, NGC 6822 (Sagittarius); IC 4703, IC 4756, M16, NGC 6604 (Serpens Cauda); B100, B101, B103, B104, B110, B111, B113, Bas 1, IC 1295, M11, M26, NGC 6649, NGC 6712 (Scutum); Cr 399 (asterism), M27, NGC 6802, NGC 6823, NGC 6834, NGC 6940, St 1 (Vulpecula)
Top ten binocular deep-sky objects for August: Cr 399, IC 4756, M8, M11, M17, M22, M24, M25, M27, NGC 6633 (IC 4756 and NGC 6633 are collectively known as the Binocular Double Cluster)
Top ten deep-sky objects for August: M8, M11, M16, M17, M20, M22, M24, M27, M55, M57
Challenge deep-sky object for August: Abell 53 (Aquila)
The objects listed above are located between 18:00 and 20:00 hours of right ascension.
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Minor Planet Occultation Updates:
This email describes updates for minor planet occultations for August 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: *****
Aug 4 (404) ARSINOë: No update for this event.
Aug 5 (307261) 2002MS4: No update for this event.
Aug 5 (585) BILKIS: Star Mag 12.2, Max dur 3.1 sec, Mag Drop 3.1
West Australia, Northern Territory and Queensland, passing near Alice Springs.
Details: http://occultations.org.nz/planet/2020/updates/200805_585_65680_u.htm
***** Aug 5 (1588) DESCAMISADA: Star Mag 9.7, Max dur 1.8 sec, Mag Drop 5.7
Significantly uncertain path across New South Wales and Victoria, passing near Melbourne and Geelong.
Details: http://occultations.org.nz/planet/2020/updates/200805_1588_67238_u.htm
Aug 5 (893) LEOPOLDINA: Star Mag 12.2, Max dur 6.7 sec, Mag Drop 1.8
Queensland and South Australia, passing over Ingham and Cardwell, near Townsville, Birdsville and Ceduna.
Details: http://occultations.org.nz/planet/2020/updates/200805_893_65682_u.htm
Aug 7 (764) GEDANIA: Star Mag 11.7, Max dur 5.3 sec, Mag Drop 2.9
New South Wales, South Australia and West Australia, passing over Port Macquarie, Broken Hill, Kalgoorlie and Cervantes.
Details: http://occultations.org.nz/planet/2020/updates/200807_764_65692_u.htm
Aug 7 (523711) 2014JH80: No update for this event.
Aug 8 (1280) BAILLAUDA: Marginal event during evening twilight over central New South Wales
***** Aug 8 (693) ZERBINETTA: Star Mag 11.0, Max dur 13.9 sec, Mag Drop 3.3
Slightly uncertain path across Tasmania, Victoria, South Australia and West Australia, passing over Horsham, Adelaide, Whyalla and Port Hedland.
Details: http://occultations.org.nz/planet/2020/updates/200808_693_65704_u.htm
Aug 9 (185) EUNIKE: No update for this event.
Aug 9 (1096) REUNERTA: Star Mag 10.8, Max dur 4.5 sec, Mag Drop 4.2
Path across southern Victoria.
Details: http://occultations.org.nz/planet/2020/updates/200809_1096_73042_u.htm
Aug 9 (10370) HYLONOME: No update for this event.
Aug 10 (1394) ALGOA: Star Mag 10.3, Max dur 2.0 sec, Mag Drop 4.2
Significantly uncertain path across northern New South Wales, South Australia and southern West Australia, passing over Kempsey and Tamworth.
Details: http://occultations.org.nz/planet/2020/updates/200810_1394_67242_u.htm
***** Aug 10 (1817) KATANGA: Star Mag 8.9, Max dur 1.3 sec, Mag Drop 6.6
Large uncertainty path across eastern Queensland and north-western New South Wales, passing near Gladstone, Ipswich and Lismore.
Details: http://occultations.org.nz/planet/2020/updates/200810_1817_73044_u.htm
Aug 14 (3731) HANCOCK: Star Mag 9.3, Max dur 2.6 sec, Mag Drop 7.4
Slightly uncertain path across central West Australia, central Northern Territory and northern Queensland, passing near Mount Isa and over Innisfail.
Details: http://occultations.org.nz/planet/2020/updates/200814_3731_67244_u.htm
Aug 14 (1867) DEIPHOBUS: Star Mag 12.5, Max dur 7.1 sec, Mag Drop 3.8
Wide path across South Australia, north-western New South Wales and central Queensland, passing over Port Pirie, Whyalla and Mackay, and near Adelaide, Broken Hill and Rockhampton.
Details: http://occultations.org.nz/planet/2020/updates/200814_1867_65756_u.htm
***** Aug 15 (1177) GONNESSIA: Star Mag 12.3, Max dur 14.8 sec, Mag Drop 2.6
Path across New Zealand and Tasmania, passing over Auckland and Hobart.
Details: http://occultations.org.nz/planet/2020/updates/200815_1177_65762_u.htm
Aug 16 (307261) 2002MS4: No update for this event.
Aug 16 (302) CLARISSA: Star Mag 12.3, Max dur 10.8 sec, Mag Drop 2.8
New Zealand, southern Tasmania and south-western West Australia, passing over Dunedin, near Hobart and Bunbury.
Details: http://occultations.org.nz/planet/2020/updates/200816_302_65770_u.htm
Aug 16 (336) LACADIERA: Star Mag 12.5, Max dur 15.8 sec, Mag Drop 0.8
Path across Queensland, Northern Territory, north-western South Australia and southern West Australia, running from Ayr to Cape Leeuwin, passing near Townsville and Bunbury.
Details: http://occultations.org.nz/planet/2020/updates/200816_336_65772_u.htm
Aug 17 (1360) TARKA: Star Mag 10.6, Max dur 1.2 sec, Mag Drop 5.3
Somewhat uncertain path across southern West Australia, northern South Australia and Queensland.
Details: http://occultations.org.nz/planet/2020/updates/200817_1360_73052_u.htm
Aug 17 (1108) DEMETER: Star Mag 10.5, Max dur 5.6 sec, Mag Drop 3.9
Slightly uncertain path across northern Queensland, Northern Territory and southern West Australia, running from Mossman to Point D'Entrecasteaux, passing near Kalgoorlie.
Details: http://occultations.org.nz/planet/2020/updates/200817_1108_73054_u.htm
Aug 18 (177) IRMA: Star Mag 11.9, Max dur 4.5 sec, Mag Drop 1.9
Southern West Australia, north-western South Australia, southern Northern Territory and northern Queensland, passing over Bunbury, Kalgoorlie and Ingham.
Details: http://occultations.org.nz/planet/2020/updates/200818_177_65790_u.htm
Aug 21 2008LC18: Extremely low probability TNO event across Australia.
***** Aug 22 (699) HELA: Star Mag 10.2, Max dur 3.7 sec, Mag Drop 3.4
Significantly uncertain path across South Australia, Victoria and New Zealand, passing over Victor Harbour, Nhill, Bendigo, Orbost and Christchurch.
Details: http://occultations.org.nz/planet/2020/updates/200822_699_67254_u.htm
Aug 22 (308) POLYXO: Star Mag 11.4, Max dur 13.4 sec, Mag Drop 0.8
Northern Tasmania and New Zealand, passing over Auckland and Launceston.
Details: http://occultations.org.nz/planet/2020/updates/200822_308_65808_u.htm
Aug 22 (471) PAPAGENA: Star Mag 11.6, Max dur 13.6 sec, Mag Drop 0.3
West Australia, central Australia and Queensland, running from Exmouth to Ballina.
Details: http://occultations.org.nz/planet/2020/updates/200822_471_65810_u.htm
Aug 22 (126) VELLEDA: Star Mag 11.9, Max dur 10.0 sec, Mag Drop 1.1
Path across Queensland, Northern Territory and West Australia.
Details: http://occultations.org.nz/planet/2020/updates/200822_126_65812_u.htm
Aug 23 (186) CELUTA: Star Mag 11.4, Max dur 3.4 sec, Mag Drop 1.9
Path across Victoria and New South Wales, passing over Torquay, Geelong, Dandenong, Belgrave and Batemans Bay.
Details: http://occultations.org.nz/planet/2020/updates/200823_186_65824_u.htm
***** Aug 23 (405) THIA: Star Mag 12.4, Max dur 10.0 sec, Mag Drop 1.1
South Australia, north-western Victoria and New South Wales, passing over Adelaide, Mildura, Orange, Sydney and Newcastle.
Details: http://occultations.org.nz/planet/2020/updates/200823_405_65826_u.htm
Aug 24 (555) NORMA: Star Mag 12.2, Max dur 5.4 sec, Mag Drop 4.2
Somewhat uncertain path across southern Queensland and northern South Australia.
Details: http://occultations.org.nz/planet/2020/updates/200824_555_65832_u.htm
Aug 24 (42) ISIS: Star Mag 11.5, Max dur 6.2 sec, Mag Drop 0.8
Path across Northern Territory and Queensland, passing over Maryborough.
Details: http://occultations.org.nz/planet/2020/updates/200824_42_65834_u.htm
Aug 24 (102) MIRIAM: Star Mag 12.1, Max dur 26.8 sec, Mag Drop 0.9
Southern West Australia, northern South Australia and southern Queensland, running from Perth to Bundaberg.
Details: http://occultations.org.nz/planet/2020/updates/200824_102_65836_u.htm
Aug 26 (415) PALATIA: Star Mag 9.6, Max dur 7.7 sec, Mag Drop 2.9
Path across New Zealand, passing over Gisborne, Napier, Whanganui and Westport.
Details: http://occultations.org.nz/planet/2020/updates/200826_415_65846_u.htm
Aug 27 (449) HAMBURGA: Star Mag 11.2, Max dur 7.9 sec, Mag Drop 3.6
Path across West Australia, Northern Territory and Queensland, passing over Dongarra.
Details: http://occultations.org.nz/planet/2020/updates/200827_449_73070_u.htm
Aug 28 (829) ACADEMIA: Star Mag 10.9, Max dur 5.5 sec, Mag Drop 4.2
West Australia and north-western Northern Territory, running from Northampton to Darwin.
Details: http://occultations.org.nz/planet/2020/updates/200828_829_73072_u.htm
***** Aug 29 (322) PHAEO: Star Mag 9.9, Max dur 7.1 sec, Mag Drop 4.0
Across Queensland, New South Wales and South Australia, running from Port Augusta to Coolangatta.
Details: http://occultations.org.nz/planet/2020/updates/200829_322_65862_u.htm
Aug 29 (1868) THERSITES: Star Mag 12.5, Max dur 4.2 sec, Mag Drop 3.6
Somewhat uncertain path across south-eastern New South Wales, eastern Victoria and Tasmania.
Details: http://occultations.org.nz/planet/2020/updates/200829_1868_65866_u.htm
Aug 30 (588) ACHILLES: Star Mag 11.9, Max dur 9.5 sec, Mag Drop 3.9
Path across New Zealand, passing over Dunedin and Invercargill and near Christchurch.
Details: http://occultations.org.nz/planet/2020/updates/200830_588_65872_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
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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/
Twitter
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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