* Astronomy

Title: Quaoar: A Rock in the Kuiper belt
Authors: W. C. Fraser, M. E. Brown

Here we report WFPC2 observations of the Quaoar-Weywot Kuiper belt binary. From these observations we find that Weywot is on an elliptical orbit with eccentricity of 0.14 ±0.04, period of 12.438 ±0.005 days, and a semi-major axis of 1.45 ±0.08 x 104 km. The orbit reveals a surprisingly high Quaoar-Weywot system mass of 1.6±0.3 x10^21 kg. Using the surface properties of the Uranian and Neptunian satellites as a proxy for Quaoar's surface, we reanalyse the size estimate from Brown and Trujillo (2004). We find, from a mean of available published size estimates, a diameter for Quaoar of 890 ±70 km. We find Quaoar's density to be
ho = 4.2 ±1.3 g cm^-3, possibly the highest density in the Kuiper belt.

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The International Astronomical Union (IAU) has approved the name "Weywot" for the transneptunian minor planet (50000) Quaoar.

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Discovered	in the `thirteenth` zodiac sign Ophiuchus in June 4 ,2002, with the Palomar Observatory's 48-inch Oschin Telescope by Chad Trujillo and Mike Brown. The rock is roughly about 1,250 kilometres (780 miles) in diameter, half Pluto's size. It orbits the Sun every 288 years, mostly beyond Pluto's orbit. At 6.5 billion kilometres (4 billion miles) from the Sun, it is the most distant thing in the solar system The object has a provisional name of 2002 LM60. However, astronomers involved in the discovery at Caltech University in Southern California have dubbed it Quaoar (pronounced kwa-whar), after the creation force of the Tongva tribe of the Los Angeles basin.
	According to legend, Quaoar "came down from heaven; and, after reducing chaos to order, laid out the world on the back of seven giants. He then, singing and dancing, created the lower animals, and then mankind." Quaoar, as an official name, will have to await approval from the International Astronomical Union.
Update: December 8 2004	Quaoar. Quaoar dates back to the formation of the solar system . And little is known about their composition because they are so distant and faint. However, new observations with the 8-metre Subaru telescope in Hawaii have revealed the spectral signature of crystalline water-ice - and possibly ammonia hydrate (a natural anti-freeze); both substances should be destroyed over a few million years by particle irradiation. The detection of crystalline ice suggests that Quaoar is or was being heated by something other than the Sun, as it could only be warmed to a maximum of -223°C (50 K) by the radiation. The heat energy needed could come from within Quaoar itself. Objects larger than 400 kilometres across are thought to contain enough heat - from the radioactive decay of rocks such as uranium - to harbour internal processes. This heat could melt ice deep in Quaoar's core. The melt water could then spring toward the surface and refreeze as crystalline ice via a process of volcanism. Another explanation for the crystalline ice is that micrometeorite impacts could have exposed ancient crystalline ice formed four billion years ago. Alternatively, these same impacts could provide enough heat , upto at least -163°C (110 K), to crystallise the "jumbled" ice already on the planet's surface. Below that temperature, water molecules stick together in random patterns to form amorphous ice.
Click for enlargement:	Quaoar.
	Download the raw data from Caltech.
Fewer than 1000 objects	2003 EL61 and 2003UB313 have been identified in a region of our solar system known as the Kuiper Belt, which extends beyond Pluto and at least one-fifth One big Kuiper Belt Object (or KBO), called Varuna, was found in 2000 and is about 40 percent as big as Pluto. Another large KBO is 2001 KX76 which was the record-holder for size in the far-out belt until now. (discounting distant Sedna.) Quaoar's orbit is close to the plane in which most of the other planets orbit, and it`s spin axis is tilted about 7.9% compared to the plane of its orbit. It's eccentricity (a measure of the ellipticity of a circle) is less than 0.04, meaning that it's distance from the sun only changes by about 8% over the course of a Quaoar year (which is 285 Earth years). the way to the nearest star.
	Quaoar has a larger volume than all known asteroids combined. It's probably made mostly of low-density ices mixed with rock, similar to the makeup of a comet. If so, Quaoar's mass is probably only one-third that of the asteroid belt. It`s magnitude is 18.5 ,with an albedo of 12 ( probably too high)
New Trans-Neptunian Object	2003 EL61 A new icy object, designated 2003 EL61, has been found. It is at least 1,500km across. It orbits just beyond the orbit of Pluto. to read more
	# Barycentric osculating elements in ICRS at epoch 2445471.8: a 43.373493 ± 0.009720 AU e 0.037457 ± 0.000055 i 7.992 ± 0.000 deg Node 188.923 ± 0.001 deg Arg of Peri 156.292 ± 0.242 deg Time of Peri 2478635.182 ± 76.022 JD Or get coordinates from Ephemeris (type in 2002 LM60).