[en] 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 (1AU 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+/-6kilometres, density 2.52+/-0.05 grams per cm[SUP]3[/SUP] and a high visible geometric albedo, . No nitrogen, argon or methane atmospheres are detected with surface pressure larger than ~1nanobar, 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.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Sicardy, B.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Ortiz, J. L.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Assafin, M.; Observatório do Valongo/UFRJ, Ladeira Pedro Antonio 43, CEP 20.080-090 Rio de Janeiro, RJ, Brazil
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Maury, A.; San Pedro de Atacama Celestial Explorations, Casilla 21, San Pedro de Atacama, Chile
Lellouch, Emmanuel; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Hutton, R Gil; Complejo Astronómico El Leoncito (CASLEO) and San Juan National University, Avenida España 1512 sur, J5402DSP, San Juan, Argentina
Braga-Ribas, F.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Colas, F.; IMCCE-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Lille 1, 77 Avenue Denfert-Rochereau, 75014 Paris, France
Hestroffer, D.; IMCCE-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Lille 1, 77 Avenue Denfert-Rochereau, 75014 Paris, France
Lecacheux, J.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Roques, F.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Santos-Sanz, P.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Widemann, T.; LESIA-Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris-Diderot, 11, Rue Marcelin Berthelot, 92195 Meudon cedex, France
Morales, N.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Duffard, R.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Thirouin, A.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Castro-Tirado, A. J.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Jelínek, M.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Kubánek, P.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Sota, A.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Sánchez-Ramírez, R.; Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
Andrei, A. H.; Observatório do Valongo/UFRJ, Ladeira Pedro Antonio 43, CEP 20.080-090 Rio de Janeiro, RJ, Brazil
Camargo, J. I. B.; Observatório do Valongo/UFRJ, Ladeira Pedro Antonio 43, CEP 20.080-090 Rio de Janeiro, RJ, Brazil
da Silva Neto, D. N.; Observatório Nacional/MCT, Rua General José Cristino 77, CEP 20921-400 Rio de Janeiro, RJ, Brazil
Gomes, A Ramos; Observatório do Valongo/UFRJ, Ladeira Pedro Antonio 43, CEP 20.080-090 Rio de Janeiro, RJ, Brazil
Martins, R Vieira; Observatório do Valongo/UFRJ, Ladeira Pedro Antonio 43, CEP 20.080-090 Rio de Janeiro, RJ, Brazil
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Manfroid, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Tozzi, G. P.; INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy
Harlingten, C.; Caisey Harlingten Observatory, The Grange, Scarrow Beck Road, Erpingham, Norfolk NR11 7QX, UK
Saravia, S.; San Pedro de Atacama Celestial Explorations, Casilla 21, San Pedro de Atacama, Chile
Behrend, R.; Observatoire de Genève, CH-1290 Sauverny, Switzerland
Mottola, S.; DLR - German Aerospace Center, Rutherfordstrasse 2, 12489 Berlin, Germany
Castro, A.; Sociedad Malagueña de Astronomía, Centro Cultural José María Gutiérrez Romero, Calle República Argentina 9, 29016 Málaga, Spain
de La Cueva, I.; Astroimagen, Abad y Lasierra 58Bis, 07800 Ibiza, Spain
Muler, G.; Observatorio Nazaret, 35539 Nazaret, Lanzarote, Spain
Steele, I. A.; Liverpool JMU, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK
Cebrián, M.; Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
Montañés-Rodríguez, P.; Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
Oscoz, A.; Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
Weaver, D.; Observatório Astronomico Christus, Colégio Christus, Rua João Carvalho 630, Aldeota, CEP 60140140, Fortaleza, CE, Brazil
Jacques, C.; Observatório CEAMIG-REA, CEP31545-120, Belo Horizonte, MG, Brazil
Corradi, W. J. B.; Departamento de Física - Instituto de Ciências Exatas - Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
Santos, F. P.; Departamento de Física - Instituto de Ciências Exatas - Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
Reis, W.; Departamento de Física - Instituto de Ciências Exatas - Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
Milone, A.; Instituto Nacional de Pesquisas Espaciais (INPE-MCT), Divisão de Astrofísica, Avenida dos Astronautas, 1758, São José dos Campos, 12227-010, SP, Brazil
Emilio, M.; Universidade Estadual de Ponta Grossa, O.A. - DEGEO, Avenida Carlos Cavalcanti 4748, Ponta Grossa 84030-900, PR, Brazil
Gutiérrez, L.; Instituto de Astronomía, Universidad Nacional Autónoma de México, Carretera Tijuana-Ensenada, km 103, 22860 Ensenada, BC, Mexico
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