Authors: Braga Ribas, F.; Sicardy, B.; Ortiz, J. L.; Lellouch, E.; Tancredi, G.; Lecacheux, J.; Vieira Martins, R.; Camargo, J. I. B.; Assafin, M.; Behrend, R.; Vachier, F.; Colas, F.; Morales, N.; Maury, A.; Emilio, M.; Amorim, A.; Unda Sanzana, E.; Roland, S.; Bruzzone, S.; Almeida, L. A.; Rodrigues, C. V.; Jacques, C.; Gil Hutton, Ricardo Alfredo; Vanzi, L.; Milone, A. C.; Schoenell, W.; Salvo, R.; Almenares, L.; Jehin, E; Manfroid, J.; Sposetti, S.; Tanga, P.; Klotz, A.; Frappa, E.; Cacella, P.; Colque, J. P.; Neves, C.; Alvarez, E. M.; Gillon, M.; Pimentel, E.; Giacchini, B.; Roques, F.; Widemann, T.; Magalhães, V. S.; Thirouin, A.; Duffard, Rene Damian; Leiva, R.; Toledo, I.; Capeche, J.; Beisker, W.; Pollock, J.; Cedeno Montaña, C. E.; Ivarsen, K; Reichart, D.; Haislip, J.; Lacluyze, A.
Publication Date: 2013.
Language: English.
Abstract:
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 Requiv = 555±2.5 km and geometric visual albedo pV = 0.109±0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of = 0.087+0.0268 −0.0175, an equatorial radius of 569+24 −17 km, and a density of 1.99 ± 0.46 g cm−3. 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.
Author affiliation: Braga Ribas, F.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . Laboratoire d;
Author affiliation: Sicardy, B.. Laboratoire d; . Universite Pierre Et Marie Curie; Francia;
Author affiliation: Ortiz, J. L.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España;
Author affiliation: Lellouch, E.. Laboratoire d;
Author affiliation: Tancredi, G.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Lecacheux, J.. Laboratoire d;
Author affiliation: Vieira Martins, R.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . L; . Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil;
Author affiliation: Camargo, J. I. B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil;
Author affiliation: Assafin, M.. Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil;
Author affiliation: Behrend, R.. Observatoire de Geneve; Suiza;
Author affiliation: Vachier, F.. L;
Author affiliation: Colas, F.. L;
Author affiliation: Morales, N.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España;
Author affiliation: Maury, A.. San Pedro de Atacama Celestial Explorations, Chile;
Author affiliation: Emilio, M.. Universidad Stadual de Ponta Grossa; Brasil;
Author affiliation: Amorim, A.. Universidade Federal Da Santa Catarina; Brasil;
Author affiliation: Unda Sanzana, E.. Universidad de Antofagasta. Unidad de Astronomía; Chile;
Author affiliation: Roland, S.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Bruzzone, S.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Almeida, L. A.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil;
Author affiliation: Rodrigues, C. V.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil;
Author affiliation: Jacques, C.. Centro de Estudos Astronomicos de Minas Gerais; Brasil;
Author affiliation: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Juan. Complejo Astronómico; Argentina
Author affiliation: Vanzi, L.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile;
Author affiliation: Milone, A. C.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil;
Author affiliation: Schoenell, W.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; . Universidade Federal Da Santa Catarina; Brasil;
Author affiliation: Salvo, R.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Almenares, L.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Jehin, E. Université de Liège. Institut d’Astrophysique; Belgica;
Author affiliation: Manfroid, J.. Université de Liège. Institut d’Astrophysique; Belgica;
Author affiliation: Sposetti, S.. Gnosca Observatory, Suiza;
Author affiliation: Tanga, P.. Observatoire de la Cote D; . Universite de Sophia Antipolis. Laboratoire Lagrange; Francia;
Author affiliation: Klotz, A.. Université Toulouse III “Paul Sabatier”. Observatoire Midi-Pyrénées. Institut de Recherche en Astrophysique et Planétologie; Francia;
Author affiliation: Frappa, E.. Euraster, Francia;
Author affiliation: Cacella, P.. Rede de Astronomia Observacional; Brasil;
Author affiliation: Colque, J. P.. Universidad de Antofagasta. Unidad de Astronomía; Chile;
Author affiliation: Neves, C.. Universidad Stadual de Ponta Grossa; Brasil;
Author affiliation: Alvarez, E. M.. Observatorio Los Algarrobos, Uruguay;
Author affiliation: Gillon, M.. Université de Liège. Institut d’Astrophysique; Belgica;
Author affiliation: Pimentel, E.. Centro de Estudos Astronomicos de Minas Gerais; Brasil;
Author affiliation: Giacchini, B.. Centro de Estudos Astronomicos de Minas Gerais; Brasil;
Author affiliation: Roques, F.. Laboratoire d;
Author affiliation: Widemann, T.. Laboratoire d;
Author affiliation: Magalhães, V. S.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil;
Author affiliation: Thirouin, A.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España;
Author affiliation: Duffard, Rene Damian. Centro Informático Científico de Andalucía; España; . Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España;
Author affiliation: Leiva, R.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile;
Author affiliation: Toledo, I.. Joint Atacama Large Millimeter/submillimeter Array Observatory; Chile;
Author affiliation: Capeche, J.. Observatorio Astronomico Los Molinos; Uruguay;
Author affiliation: Beisker, W.. International Occultation Timing Association European Section; Alemania;
Author affiliation: Pollock, J.. Appalachian State University. Department of Physics and Astronomy; Estados Unidos;
Author affiliation: Cedeno Montaña, C. E.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil;
Author affiliation: Ivarsen, K. University of North Carolina. Physics and Astronomy Department; Estados Unidos;
Author affiliation: Reichart, D.. University of North Carolina. Physics and Astronomy Department; Estados Unidos;
Author affiliation: Haislip, J.. University of North Carolina. Physics and Astronomy Department; Estados Unidos;
Author affiliation: Lacluyze, A.. University of North Carolina. Physics and Astronomy Department; Estados Unidos;
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas