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Refined physical parameters for Chariklo's body and rings from stellar occultations observed between 2013 and 2020
Fecha
2021-08-01Registro en:
Astronomy and Astrophysics, v. 652.
1432-0746
0004-6361
10.1051/0004-6361/202141543
2-s2.0-85113911250
Autor
Sorbonne Paris Cité
Laboratório Interinstitucional de E-Astronomia - LIneA
Observatório Nacional/MCTI
Federal University of Technology - Paraná (UTFPR / DAFIS)
Institut Polytechnique des Sciences Avancées Ipsa
Univ. Lille
Universidade Estadual Paulista (UNESP)
Laboratoire Lagrange
Universidad de Chile
IAA-CSIC
Universidade Federal do Rio de Janeiro (UFRJ)
International Occultation Timing Association / European Section
Internationale Amateursternwarte E.V. (IAS)
Royal Observatory
University of Central Florida
BRAMON-Brazilian Meteor Observation Network
Universidade Estadual de Mato Grosso do Sul (UEMS)
Universidad Nacional de Córdoba-CONICET
University of Namibia
North-West University
Observatoire Midi-Pyrénées
Southwest Research Institute
Smpw Q25 CJ1 LT10B
Association of Argentine Observatories of Minor Bodies (AOACM))
Universidad de Antofagasta
Ciel and Espace
Supa School of Physics and Astronomy North Haugh
Universidade Estadual de Ponta Grossa (UEPG)
Summit Kinetics Inc
Panamanian Observatory in San Pedro de Atacama - Opspa
Southern University of Science and Technology
Centro Brasileiro de Pesquisas Físicas
Trans-Tasman Occultation Alliance (TTOA)
Association Réunionnaise Pour l'Etude du Ciel Austral - Areca
Astronomy and Informatics Nicolaus Copernicus University
Chungnam National University
Observatório Sonear
Université de Liège
Niels Bohr Institute
Astronomical Association of Queensland
University of North Carolina
Central (Pulkovo) Observatory of the Russian Academy of Sciences
Lowell Observatory
Atmospheric and Planetary Sciences
The Astronomical Research Institute
International Occultation Timing Association (IOTA)
Nasa Johnson Space Center Astronomical Society
Universidade Estadual Do Oeste Do Paraná (Unioeste)
Polo Astronômico Casimiro Montenegro Filho/FPTI-BR
San Pedro de Atacama Celestial Explorations - Space
Comisión Nacional de Investigación y Desarrollo Aeroespacial Del Perú - Conida
Cp Cambrune Carumas
Appalachian State University
Astrocan Clube de Astronomia Nhandeara
Ku Leuven
The Open University
Association des Étoiles Pour Tous
Observatorio Astronómico Córdoba Unc
Observatoire des Makes
Pontificia Universidad Catolica de Chile
Millennium Institute of Astrophysics
Institución
Resumen
Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and ring structure. Results. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3σ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo's detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8-1.5+1.4, 135.2-2.8+1.4, and 99.1-2.7+5.4 km. Ultimately, we provided seven astrometric positions at a milliarcsecond accuracy level, based on Gaia EDR3, and use it to improve Chariklo's ephemeris.