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TOPIC: 2003UB313 / The Tenth Planet


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RE: 2003UB313 / The Tenth Planet
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Former 'tenth planet' may be smaller than Pluto

The bragging rights in the outer solar system may have shifted over the weekend. If the early results hold up, this time it's the dwarf planet Eris's turn to be demoted, and Pluto might have just regained its status as the largest object in the Kuiper Belt, the ring of icy bodies beyond Neptune.
The scene for this drama is high in the Chilean Andes, where on Saturday three teams of astronomers caught Eris in the act of passing directly in front of a star. Astronomers had known about this occultation well in advance, but the predicted path had shifted up and down along South America, leaving astronomers unsure who - if anyone - might see the event.
Well, the news from Chile is that three observing teams, all using relatively modest telescopes, saw the star blink out. Emmanuël Jehin of the University of Liège, Belgium, tracked the event with the 60-cm TRAPPIST telescope at La Silla Observatory, and says the occultation lasted about 27 seconds.

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(136199) Eris
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Eris, the goddess of discord and strife and the most massive dwarf planet, is up to her usual tricks.
On Friday night Eris was predicted to pass directly in front of a relatively faint star in the constellation of Cetus. You might think that this sort of thing happens all of the time, but youd be wrong. Eris is so small in the sky and stars are such tiny points of light that, though they get close frequently, their actually intersections are rare. When they do intersect, though, something amazing happens: the star disappears. And since we know how fast Eris is moving across the sky, seeing how long the star disappears gives us a very precise measure of the size of Eris. Or, to be more exact, a very precise measure of a single chord passing through the body.

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Title: Methane and Nitrogen Abundances On Pluto and Eris
Authors: S.C. Tegler, D.M. Cornelison, W.M. Grundy, W. Romanishin, M.R. Abernathy, M.J. Bovyn, J.A. Burt, D.E. Evans, C.K. Maleszewski, Z. Thompson, F. Vilas

We present spectra of Eris from the MMT 6.5 meter telescope and Red Channel Spectrograph (5700-9800 angstroms; 5 angstroms per pix) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 meter telescope and Boller and Chivens spectrograph (7100-9400 angstroms; 2 angstroms per pix) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich (1983), and comparing methane bands in our Eris and Pluto spectra and methane bands in our laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are about 10% and about 90%, and Pluto's bulk methane and nitrogen abundances are about 3% and about 97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 micron band is seen in spectra of Pluto and Triton.

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(136199) Eris
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Icy surface of Eris dominated by nitrogen, methane

Scientists have revealed that the frozen surface of Eris-largest-known dwarf planet orbiting the Sun-is predominantly covered in nitrogen ice, similar to the surface of Pluto.
The results of the study integrated two years of work conducted in NAU''s new ice lab, in addition to astronomical observations of Eris from the Multiple Mirror Telescope Observatory from Mount Hopkins, Ariz., and of Pluto from Steward Observatory from Kitt Peak, Ariz.

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RE: 2003UB313 / The Tenth Planet
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Eris was discovered by the team of Mike Brown, Chad Trujillo, and David Rabinowitz on January 5, 2005, from images taken on October 21, 2003. The discovery was announced on July 29, 2005, the same day as Makemake and two days after Haumea.
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Eris
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Eris, formal designation 136199 Eris, is the largest known dwarf planet in the Solar System and the ninth-largest body known to orbit the Sun directly. It is approximately 2,500 kilometres in diameter and 27% more massive than Pluto.
Eris was first identified in January 2005 by a Palomar Observatory-based team led by Mike Brown, and its identity verified later that year. It is a trans-Neptunian object (TNO) native to a region of space beyond the Kuiper belt known as the scattered disc.

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RE: 2003UB313 / The Tenth Planet
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Strange weather on the icy dwarf planet Eris could be causing changes that scientists are now seeing at the methane-ice surface of this distant object in our solar system.
Eris is the largest known solar-system object beyond the orbit of Neptune. It is larger than Pluto, with a diameter of ranging somewhere between about 2,400 km and 3,000 km.
A team of researchers examined data on Eris collected from the MMT Observatory in Arizona. They specifically looked at concentrations of methane ice based on light-reflection and absorption information.
Their results show possibly nitrogen ice mixed in with the methane ice covering Eris' surface. And the relative amount of nitrogen ice increases with depth into the ice.


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RE: (136199) Eris
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Mysterious changes seen on distant dwarf planet
The surface of the largest known 'plutoid' appears to have changed in recent years, according to new measurements of how elements are layered on its icy surface. But astronomers cannot explain the cause of the apparent change.
Eris is the largest known object beyond the orbit of Neptune, weighing nearly a third more than Pluto. It travels on an elongated path around the Sun that takes about 560 years to complete.
Astronomers think the distant world is covered by a layer of frozen methane and small amounts of nitrogen ice. When it comes near the Sun, these ices are thought to vaporise from sunlit portions of the surface and condense onto regions in shadow.

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Title: Polarimetry of the dwarf planet (136199) Eris
Authors: I. Belskaya, S. Bagnulo, K. Muinonen, M.A. Barucci, G.P. Tozzi, S. Fornasier, and L. Kolokolova

Context. Study the surface properties of the transneptunian population of Solar-system bodies
Aims. We investigate the surface characteristics of the large dwarf planet (136199) Eris.
Methods. With the FORS1 instrument of the ESO VLT, we have obtained Bessell broadband R linear polarimetry and broadband V and I photometry of Eris. We have modelled the observations in terms of the coherent-backscattering mechanism to constrain the surface properties of the object.
Results. Polarimetric observations of Eris show a small negative linear polarisation without opposition surge in the phase angle range of 0.15 0.5#. The photometric data allow us to suppose a brightness opposition peak at phase angles below 0.2 0.3#. The data obtained suggest possible similarity to the polarimetric and photometric phase curves of Pluto. The measured absolute magnitude and broadband colours of Eris are HV=-1.15 mag, V R = 0.41 mag, and V I = 0.75 mag.
Conclusions. The observational data with theoretical modelling are in agreement with the surface of Eris being covered by rather large inhomogeneous particles.

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RE: 10th Planet
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October 14th 2007
Dwarf Planet 136199 Eris (2003 UB313) - Closest Approach To Earth (95.831 AU)

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