Publication Date:
2011-10-28
Description:
The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1 AU is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 UT. The event is consistent with a spherical shape for Eris, with radius 1,163 +/- 6 kilometres, density 2.52 +/- 0.05 grams per cm(3) and a high visible geometric albedo, Pv = 0.96(+0.09)(-0.04). No nitrogen, argon or methane atmospheres are detected with surface pressure larger than approximately 1 nanobar, about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sicardy, B -- Ortiz, J L -- Assafin, M -- Jehin, E -- Maury, A -- Lellouch, E -- Hutton, R Gil -- Braga-Ribas, F -- Colas, F -- Hestroffer, D -- Lecacheux, J -- Roques, F -- Santos-Sanz, P -- Widemann, T -- Morales, N -- Duffard, R -- Thirouin, A -- Castro-Tirado, A J -- Jelinek, M -- Kubanek, P -- Sota, A -- Sanchez-Ramirez, R -- Andrei, A H -- Camargo, J I B -- da Silva Neto, D N -- Gomes, A Ramos Jr -- Martins, R Vieira -- Gillon, M -- Manfroid, J -- Tozzi, G P -- Harlingten, C -- Saravia, S -- Behrend, R -- Mottola, S -- Melendo, E Garcia -- Peris, V -- Fabregat, J -- Madiedo, J M -- Cuesta, L -- Eibe, M T -- Ullan, A -- Organero, F -- Pastor, S -- de Los Reyes, J A -- Pedraz, S -- Castro, A -- de la Cueva, I -- Muler, G -- Steele, I A -- Cebrian, M -- Montanes-Rodriguez, P -- Oscoz, A -- Weaver, D -- Jacques, C -- Corradi, W J B -- Santos, F P -- Reis, W -- Milone, A -- Emilio, M -- Gutierrez, L -- Vazquez, R -- Hernandez-Toledo, H -- England -- Nature. 2011 Oct 26;478(7370):493-6. doi: 10.1038/nature10550.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉LESIA-Observatoire de Paris, CNRS, Universite Pierre et Marie Curie, Universite Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France. bruno.sicardy@obspm.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22031441" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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