Refined physical parameters for Chariklo's body and rings from stellar occultations observed between 2013 and 2020

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...

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Detalles Bibliográficos
Autores: Morgado, B.E., Sicardy, Bruno, Braga Ribas, Felipe, Desmars, Josselin, Gomes Júnior, Altair Ramos, Bérard, D., Leiva, Rodrigo, Vieira Martins, Roberto, Benedetti Rossi, G., Santos Sanz, Pablo, Camargo, Julio Ignacio Bueno, Duffard, R., Rommel, F.L., Assafin, M., Boufleur, R.C., Colas, F., Kretlow, Mike, Beisker, W., Sfair, Rafael, Snodgrass, Colin, Morales, N., Fernández Valenzuela, E., Amaral, L.S., Amarante, A., Artola, R.A., Backes, M., Bath, K. L., Bouley, S., Garcia Lambas, Diego Rodolfo, Schneiter, Ernesto Matías
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2021
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/173040
Acceso en línea:http://hdl.handle.net/11336/173040
Access Level:acceso abierto
Palabra clave:ASTEROIDS: INDIVIDUAL: CHARIKLO
METHODS: DATA ANALYSIS
METHODS: OBSERVATIONAL
MINOR PLANETS
OCCULTATIONS
PLANETS AND SATELLITES: RINGS
https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
Descripción
Sumario: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.

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