Issue |
A&A
Volume 652, August 2021
|
|
---|---|---|
Article Number | A141 | |
Number of page(s) | 29 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202141543 | |
Published online | 25 August 2021 |
Refined physical parameters for Chariklo’s body and rings from stellar occultations observed between 2013 and 2020★
1
LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot,
Sorbonne Paris Cité,
5 place Jules Janssen,
92195
Meudon,
France
e-mail: morgado.fis@gmail.com
2
Laboratório Interinstitucional de e-Astronomia - LIneA,
Rua Gal. José Cristino 77,
Rio de Janeiro,
20921-400,
Brazil
3
Observatório Nacional/MCTI,
R. General José Cristino 77, CEP
20921-400
Rio de Janeiro - RJ,
Brazil
4
Federal University of Technology - Paraná (UTFPR / DAFIS),
Rua Sete de Setembro, 3165, CEP
80230-901,
Curitiba,
PR,
Brazil
5
Institut Polytechnique des Sciences Avancées IPSA,
63 boulevard de Brandebourg,
94200
Ivry-sur-Seine,
France
6
Institut de Mécanique Céleste et de Calcul des Éphémérides, IMCCE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ. Lille,
77, Av. Denfert-Rochereau,
75014
Paris,
France
7
UNESP - São Paulo State University, Grupo de Dinâmica Orbital e Planetologia,
CEP
12516-410,
Guaratinguetá,
SP,
Brazil
8
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire,
CS 34229,
06304
Nice Cedex 4,
France
9
Departamento de Astronomía, Universidad de Chile,
Camino del Observatorio 1515,
Las Condes,
Santiago,
Chile
10
Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía s/n,
18008
Granada,
Spain
11
Universidade Federal do Rio de Janeiro - Observatório do Valongo,
Ladeira Pedro Antônio 43, CEP
20.080-090
Rio de Janeiro - RJ,
Brazil
12
International Occultation Timing Association / European Section,
Am Brombeerhag 13,
30459
Hannover,
Germany
13
Internationale Amateursternwarte e.V. (IAS),
Mittelstrasse 6,
15749
Mittenwalde,
Germany
14
Institute for Astronomy, University of Edinburgh, Royal Observatory,
Edinburgh
EH9 3HJ,
UK
15
Florida Space Institute, University of Central Florida,
12354 Research Parkway, Partnership 1,
Orlando,
FL,
USA
16
BRAMON–Brazilian Meteor Observation Network,
Nhandeara,
Brazil
17
Grupo de Matemática Aplicada e Processamento de Sinais, State University of Mato Grosso do Sul - UEMS,
Cassilândia,
CEP 79540-000,
MS,
Brazil
18
IATE-OAC, Universidad Nacional de Córdoba-CONICET,
Laprida 854,
X5000
BGR,
Córdoba,
Argentina
19
Department of Physics, Chemistry and Material Science, University of Namibia,
Private Bag 13301,
Windhoek,
Namibia
20
Centre for Space Research, North-West University,
Potchefstroom
2520,
South Africa
21
Association T60, Observatoire Midi-Pyrénées,
14 avenue Edouard Belin,
31400
Toulouse,
France
22
Southwest Research Institute,
1050 Walnut Street, Suite 300,
Boulder,
CO
80302,
USA
23
Dogsheaven Observatory,
SMPW Q25 CJ1 LT10B
Brasilia,
Brazil
24
Association of Argentine Observatories of Minor Bodies (AOACM)),
Argentina
25
Centro de Astronomía (CITEVA), Universidad de Antofagasta,
Av. Angamos 601,
Antofagasta,
Chile
26
Ciel & Espace,
Paris,
France
27
University of St Andrews, Centre for Exoplanet Science, SUPA School of Physics & Astronomy,
North Haugh,
St Andrews,
KY16 9SS,
UK
28
Universidade Estadual de Ponta Grossa (UEPG),
Ponta Grossa,
Brazil
29
Summit Kinetics Inc,
USA
30
Panamanian Observatory in San Pedro de Atacama - OPSPA,
San Pedro de Atacama,
Chile
31
Department of Physics, Southern University of Science and Technology,
Shenzhen
518055,
PR China
32
Centro Brasileiro de Pesquisas Físicas,
Rua Dr Xavier Sigaud 150,
Rio de Janeiro
22290-180,
Brazil
33
Trans-Tasman Occultation Alliance (TTOA),
Wellington
PO Box 3181,
New Zealand
34
Association Réunionnaise pour l’Etude du Ciel Austral - ARECA,
Sainte-Marie,
La Réunion,
France
35
Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University,
Grudziadzka 5,
87-100,
Torun,
Poland
36
Department of Astronomy and Space Science, Chungnam National University,
34134
Daejeon,
Republic of Korea
37
Observatório SONEAR,
Oliveira,
Brazil
38
STAR Institute, Université de Liège,
Allée du 6 août,
19C, 4000
Liège,
Belgium
39
Centre for ExoLife Sciences (CELS), Niels Bohr Institute,
øster Voldgade 5,
1350
Copenhagen,
Denmark
40
Astronomical Association of Queensland,
5 Curtis Street,
Pimpama QLD
4209,
Australia
41
Department of Physics and Astronomy, University of North Carolina,
Chapel Hill,
USA
42
Central (Pulkovo) Observatory of the Russian Academy of Sciences,
196140,
65/1 Pulkovskoye Ave.,
Saint Petersburg,
Russia
43
Lowell Observatory,
1400 W Mars Hill Road,
Flagstaff,
AZ
86001,
USA
44
Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences,
77 Massachusetts Avenue,
Cambridge,
MA
02139,
USA
45
The Astronomical Research Institute,
Ashmore,
IL,
UK
46
International Occultation Timing Association (IOTA),
PO Box 7152,
WA,
98042,
USA
47
NASA Johnson Space Center Astronomical Society,
Houston,
TX,
USA
48
Universidade Estadual do Oeste do Paraná (Unioeste),
Avenida Tarquínio Joslin dos Santos 1300,
Foz do Iguaçu,
PR,
85870-650,
Brazil
49
Polo Astronômico Casimiro Montenegro Filho/FPTI-BR,
Avenida Tancredo Neves 6731,
Foz do Iguaçu,
PR,
85867-900,
Brazil
50
San Pedro de Atacama Celestial Explorations - SPACE,
Chile
51
Comisión Nacional de Investigación y Desarrollo Aeroespacial del Perú - CONIDA,
Luis Felipe Villarán 1069,
San Isidro,
Lima,
Peru
52
Observatorio Astronómico de Moquegua,
CP Cambrune,
Carumas,
Moquegua,
Peru
53
Physics and Astronomy Department, Appalachian State University,
Boone,
NC
28608,
USA
54
Astrocan Clube de Astronomia Nhandeara,
Nhandeara,
Brazil
55
Centre for mathematical Plasma Astrophysics, Department of Mathematics,
KU Leuven, Celestijnenlaan 200B,
3001
Leuven,
Belgium
56
Centre for Electronic Imaging, Department of Physical Sciences, The Open University,
Milton Keynes,
MK7 6AA,
UK
57
Association Des Étoiles pour Tous,
19 Rue Saint Laurent,
Maisoncelles,
77320
Saint Martin du Boschet,
France
58
Observatorio Astronómico Córdoba UNC,
Laprida 854,
Córdoba,
Argentina
59
AGORA observatoire des Makes, AGORA,
18 Rue Georges Bizet,
Observatoire des Makes,
97421
La Rivière,
France
60
Institute of Astrophysics, Pontificia Universidad Catolica de Chile,
Av. Vicuña Mackenna 4860,
Santiago,
Chile
61
Millennium Institute of Astrophysics,
Chile
62
Centre of Astro-Engineering, Pontificia Universidad Catolica de Chile,
Av. Vicuña Mackenna 4860,
Santiago,
Chile
63
Department of Electrical Engineering, Pontificia Universidad Catolica de Chile,
Av. Vicuña Mackenna 4860,
Santiago,
Chile
Received:
14
June
2021
Accepted:
12
July
2021
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.
Key words: occultations / methods: observational / methods: data analysis / minor planets, asteroids: individual: Chariklo / planets and satellites: rings
Tables C.1, C.2 and lightcurves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/652/A141.
© B. E. Morgado et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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