We hurtle way beyond the asteroid belt today, for a change, to celebrate the discovery of 20000 Varuna, first spotted for what it is on November 28th 2000 by Robert S Macmillan, despite appearing on photographic plates dating back to the 1950s.
Varuna is a fairly large classical Kuiper belt object (KBO). Estimates of its size vary widely from 600 to 1000km, but even if it turns out to be at the lower end, it still ranks highly in the KBO pecking order.
Varuna has a very rapid rotation (6.34 hours) and a double-peaked light curve. it is thought to be an elongated spheroid, about half as wide again across the equator as from pole to pole.
The Hindu deity Varuna, after whom this particular oblate spheroid is named, has similar qualities to the Roman god Neptune, making it a good choice for what at the time was the largest known trans-Neptunian object.
Asteroid 235 Carolina was also discovered today, in 1883. It is one of Johann Palisa‘s collection of 122 asteroids, and came while he was going through (by his standards) a dry patch in his rock hunting career. Having discovered nine in 1882, he “only” managed two in 1883, before hitting his stride again in 1884 with six. Part of the reason for this relative scarcity was probably that Palisa spent a good portion of the year 1883 travelling to watch a total solar eclipse. The spot chosen for the expedition was near to Tahiti, in the chain of coral atolls known as the Line Islands. More specifically . . . .
We have a cubewano today! It is Kuiper-belt object 19521Chaos, which was discovered by the Deep Ecliptic Survey on November 19th, 1998. Chaos is about 600 km in diameter, and may well be a dwarf planet, not much smaller than Ixion and Varuna. It orbits between a perihelion of about 40.9 AU and an aphelion of just under 50.6 AU, and spends more than 300 Earth years completing a single orbit of the Sun (or 1 Chaotian year, obviously).
1996 – Launch of space shuttle Columbia on mission STS-80 (19 days late). At 17 days and 15 hours this became the longest shuttle mission, and comprised commander Kenneth D Cockrell, pilot Kent V Rominger, and mission specialists F Story Musgrave, Thomas D Jones, and Tamara E Jernigan. Musgrave was on his sixth flight, a record at the time, and became the only person to fly all five shuttles.
As you can probably tell from the large number in front of its name, 148780 Altjira was discovered a considerable time later than most of the other small and medium-sized solar system bodies in these pages (October 20th, 2001), but it gets a mention for a couple of reasons. Firstly, Altjira is a binary system of almost equally sized partners, comprising a primary object of something approaching 180 to 200 km diameter, and a secondary only a little less wide (probably about 150km) discovered six years later. Between them they comprise a classical Kuiper Belt object (KBO) also known as a cubewano, a name derived from the first such object discovered, (15760) 1992 QB1.
The second reason I thought this particular KBO deserved a mention was because I believe it’s the only time I’ll be referring to Aboriginal Australian mythology. Altjira is a sky god of the Aranda (or Arrernte) people of the Northern Territory, and is is credited with creating the Earth during the Dreamtime.
Altjira was discovered using the Deep Ecliptic Survey, a very successful project to find KBOs, which, between 1998 and 2005, produced the first Neptune Trojan and the first binary trans-Neptunian object (TNO), as well as dozens of centaurs and a couple of hundred classical KBOs.
1962 – Launch of Kosmos 11 (aka DS-A1 No.1) by the Soviet Union, using a Vostok 2 rocket, on October 20th, 1962, from the Mayak Launch Complex. The purpose of the “DS” missions was to test various hardware, primarily concerned with the development of anti-ballistic missile defence systems. The “DS” in the name stands for Dnepropetrovsk Sputnik. Dnipropetrovsk is the third largest city in Ukraine. Kosmos 11 managed to stay in orbit until May 18th, 1963.
Discovered on this very day in 1859 by Robert Luther,57 Mnemosyneis a main belt asteroid of about 113km across, sweeping round the Sun at 16.7km/s, and taking about five and a half years to complete one orbit. Mnemosyne is a stony “S” type asteroid, with an albedo of 0.215. S types are generally brighter than most, with Iris able to reach +7.0 at opposition.
Mnemosyne was a titaness (a daughter of Uranus and Gaia), and was mother of the nine Muses (Zeus was the father, and somehow managed to persuade Mnemosyne that they needed to sleep together for nine nights to get the job done).
It is from Mnemosyne that we get the word mnemonic.
1862 – Asteroid 75 Eurydike discovered by C H F Peters.
1878 – Asteroid 190 Ismene,a member of the Hildian family, discovered by C H F Peters. The family are named after asteroid 153 Hilda.
1884 – Asteroid 242 Kriemhild discovered.
2004 – Planetoid 120347 Salacia discovered. Salacia has an incredibly high number, but is significant because, as you will have noticed, I used the word “planetoid”, indicating it isn’t one of my normal day-to-day asteroids. This particular Kuiper belt object is estimated to be 850 km (530 miles) in diameter.
Main-belt asteroid 40 Harmoniawas discovered by Hermann Goldschmidton March 31st, 1856. It is an S-type main belt asteroid, about 107 km in diameter. One of 14 asteroids discovered by Goldschmidt, Harmonia is named after the Greek goddess of (obviously) harmony. Her Roman counterpart was Concordia (who also has an asteroid named after her, discovered in 1860). The name was chosen to mark the end of the Crimean War, which officially came to an end, with the signing of the Treaty of Paris, on the day before Harmonia was discovered.
Despite her harmonious attributes, the most popular stories surrounding this goddess involve a necklace she received on her wedding day, possibly from Hephaestus (different sources give various donors). This necklace, while it apears to have had no adverse impact on Harmonia herself, had a long life bringing misery and death to all who owned it after her.
The photograph shows a red figure oinochoe (wine jug) by the Mannheim painter. Eriphyle is being bribed by Polynices to get her husband Amphiaraüs to become embroiled in the battle of the “Seven Against Thebes”. She was later to do the same to her son, Alcmaeon. When he found out what she’d been up to, he killed her.
1886 – Asteroid 254 Augusta was discovered by Austrian astronomer Johann Palisa on March 31st 1886. It is a small main belt asteroid of about 12km diameter, and is of spectral type “S”. It was named after Auguste von Littrow, the widow of astronomer Carl Ludwig von Littrow.
1886 – Asteroid 255 Oppavia is another main belt asteroid, and was also discovered on March 31st 1886 by Johann Palisa. It’s rather larger than Augusta, at 57 km wide, and is a P-type.
Opava is the name of the town where Palisa was born. It is currently in the Czech Republic, but at the time of Palisa’s birth it was part of the territory known as Austrian Silesia (following the War of Austrian Succession) which is why he is an Austrian astronomer. Opava’s most famous daughter is Joy Adamson, author of “Born Free”.
2005 – The large trans-Neptunian object (TNO) and Kuiper Belt object (KBO) Makemake was discovered nine years ago today. As well as being as TNO, Makemake’s size allows it to bask in the title “dwarf planet”, and while various studies give varying opinions regarding the precise extent of that size, the prevailing view seems to be that it’s around 1,400 to 1500 km in diameter. Unfortunately for early planet hunters, though, it’s also a very long way away, (magnitude 16.7 at opposition) and has an unusually high orbital inclination, which is why it was only discovered so recently.
Spectral analysis of the surface suggest that up to 90% is covered in ices of methane and Nitrogen, with “tholins” also present, giving Makemake a reddish appearance visually. It has almost no atmosphere, and (unusually for such a large TNO) no satellites.
1891 – Discovery of asteroid 308 Polyxo by Alphonse Borrelly. Measuring 130 km across, Polyxo is one of the rare, mysterious T-type asteroids. There are multiple Polyxo’s in Greek mythology, but I believe this particular asteroid was named after one of the Hyades.
Asteroid 170 Maria was discovered on January 10th 1877 by H J Perrotin. It is an S-type asteroid in the main belt, is 44.3 km in diameter, and rotates every 13.14 hours.
Maria was named after the sister of Antonio Abetti, the man who worked out its orbit.
Maria is the head of a small family of similarly inclined asteroids orbiting between 2.5 and 2.7 AU from the Sun.
1894 – Asteroid 381 Myrrha discovered by Auguste Charlois, and named after the mother of Adonis.
1936 – American astronomer and co-discoverer of the cosmic microwave background radiation, Robert Woodrow Wilson born in Houston, Texas. Wilson was awarded (jointly with Pyotr Kapitsa and Arno Penzias) the Nobel Prize in Physics, 1978, for the discovery.
1969 – Launch of the Venera 6 spacecraft by the USSR, five days after Verera 5. The mission to Venus was a success, with 51 minutes of data regarding the Venusian atmosphere being returned while the craft descended to the surface by parachute, before being destroyed by that same atmosphere.
2002 – Discovery of classical Kuiper Belt object 2002 AW197 by six astronomers using observations from Mauna Kea and Palomar (deciding where and by whom these things were discovered was a lot easier in the 19th century when they were usually discovered by one man in Austria or France). 2002 AW197 might be a dwarf planet, but this has yet to be confirmed.