Article (Scientific journals)
The Size, Shape, Albedo, Density, and Atmospheric Limit of Transneptunian Object (50000) Quaoar from Multi-chord Stellar Occultations
Braga-Ribas, F.; Sicardy, B.; Ortiz, J. L. et al.
2013In Astrophysical Journal, 773, p. 26
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Keywords :
Kuiper belt objects: individual: 50000 Quaoar; occultations; planets and satellites: atmospheres; planets and satellites: fundamental parameters
Abstract :
[en] We present results derived from the first multi-chord stellar occultations by the transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, and from a single-chord occultation observed on 2012 October 15. If the timing of the five chords obtained in 2011 were correct, then Quaoar would possess topographic features (crater or mountain) that would be too large for a body of this mass. An alternative model consists in applying time shifts to some chords to account for possible timing errors. Satisfactory elliptical fits to the chords are then possible, yielding an equivalent radius R [SUB]equiv[/SUB] = 555 ± 2.5 km and geometric visual albedo p[SUB]V[/SUB] = 0.109 ± 0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of \epsilon = 0.087^{+0.0268}_{-0.0175}, an equatorial radius of 569^{+24}_{-17} km, and a density of 1.99 ± 0.46 g cm[SUP]–3[/SUP]. The orientation of our preferred solution in the plane of the sky implies that Quaoar's satellite Weywot cannot have an equatorial orbit. Finally, we detect no global atmosphere around Quaoar, considering a pressure upper limit of about 20 nbar for a pure methane atmosphere.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Braga-Ribas, F.;  Observatório Nacional, Rio de Janeiro, Brazil ; Observatoire de Paris, LESIA, F-92195 Meudon, France ; Current address: Rua General José Cristino, 77, CEP 20921-400, Rio de Janeiro, RJ, Brazil.
Sicardy, B.;  Observatoire de Paris, LESIA, F-92195 Meudon, France ; Université Pierre et Marie Curie, F-75252 Paris, France
Ortiz, J. L.;  Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain
Lellouch, Emmanuel;  Observatoire de Paris, LESIA, F-92195 Meudon, France
Tancredi, G.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Lecacheux, J.;  Observatoire de Paris, LESIA, F-92195 Meudon, France
Vieira-Martins, R.;  Observatório Nacional, Rio de Janeiro, Brazil ; Observatoire de Paris, IMCCE, F-75014 Paris, France ; Observatório do Valongo/UFRJ, Rio de Janeiro, Brazil
Camargo, J. I. B.;  Observatório Nacional, Rio de Janeiro, Brazil
Assafin, M.;  Observatório do Valongo/UFRJ, Rio de Janeiro, Brazil
Behrend, R.;  Observatoire de Genève, Sauverny, Switzerland
Vachier, F.;  Observatoire de Paris, IMCCE, F-75014 Paris, France
Colas, F.;  Observatoire de Paris, IMCCE, F-75014 Paris, France
Morales, N.;  Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain
Maury, A.;  San Pedro de Atacama Celestial Explorations, San Pedro de Atacama, Chile
Emilio, M.;  Universidade Estadual de Ponta Grossa, Ponta Grossa, Brazil
Amorim, A.;  Universidade Federal de Santa Catarina, Florianópolis, Brazil
Unda-Sanzana, E.;  Unidad de Astronomía, Universidad de Antofagasta, Antofagasta, Chile
Roland, S.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Bruzzone, S.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Almeida, L. A.;  Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil
Rodrigues, C. V.;  Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil
Jacques, C.;  Centro de Estudos Astronômicos de Minas Gerais (CEAMIG), Belo Horizonte, Brazil
Gil-Hutton, R.;  Complejo Astronómico El Leoncito and San Juan National University, San Juan, Argentina
Vanzi, L.;  Department of Electrical Engineering and Center of Astro-Engineering, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile
Milone, A. C.;  Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil
Schoenell, W.;  Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain ; Universidade Federal de Santa Catarina, Florianópolis, Brazil
Salvo, R.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Almenares, L.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Jehin, Emmanuel  ;  Université de Liège - ULiège
Manfroid, Jean  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Sposetti, S.;  Gnosca Observatory, Gnosca, Switzerland
Tanga, P.;  Laboratoire Lagrange, Université de Sophia Antipolis, Observatoire de la Côte d'Azur, CNRS UMS7293, F-06304 NICE Cedex 4, France
Klotz, A.;  Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse, France
Frappa, E.;  Euraster, 1B cours J. Bouchard, F-42000 St-Etienne, France
Cacella, P.;  Rede de Astronomia Observacional, Brasilia, Brazil
Colque, J. P.;  Unidad de Astronomía, Universidad de Antofagasta, Antofagasta, Chile
Neves, C.;  Universidade Estadual de Ponta Grossa, Ponta Grossa, Brazil
Alvarez, E. M.;  Observatorio Los Algarrobos, Salto, Uruguay
Gillon, Michaël  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Pimentel, E.;  Centro de Estudos Astronômicos de Minas Gerais (CEAMIG), Belo Horizonte, Brazil
Giacchini, B.;  Centro de Estudos Astronômicos de Minas Gerais (CEAMIG), Belo Horizonte, Brazil
Roques, F.;  Observatoire de Paris, LESIA, F-92195 Meudon, France
Widemann, T.;  Observatoire de Paris, LESIA, F-92195 Meudon, France
Magalhães, V. S.;  Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil
Thirouin, A.;  Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain
Duffard, R.;  Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain
Leiva, R.;  Department of Electrical Engineering and Center of Astro-Engineering, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile
Toledo, I.;  Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura, Santiago, Chile
Capeche, J.;  Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay
Beisker, W.;  International Occultation Timing Association-European Section, D-30459 Hannover, Germany
Pollock, J.;  Department of Physics and Astronomy, Appalachian State University, Boone, NC 28608, USA
Cedeño Montaña, C. E.;  Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil
Ivarsen, K.;  Physics and Astronomy Department, University of North Carolina, Chapel Hill, NC, USA
Reichart, D.;  Physics and Astronomy Department, University of North Carolina, Chapel Hill, NC, USA
Haislip, J.;  Physics and Astronomy Department, University of North Carolina, Chapel Hill, NC, USA
Lacluyze, A.;  Physics and Astronomy Department, University of North Carolina, Chapel Hill, NC, USA)
More authors (46 more) Less
Language :
English
Title :
The Size, Shape, Albedo, Density, and Atmospheric Limit of Transneptunian Object (50000) Quaoar from Multi-chord Stellar Occultations
Publication date :
01 August 2013
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, United States - Illinois
Volume :
773
Pages :
26
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
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