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Nature. 2017 Oct 11;550(7675):219-223. doi: 10.1038/nature24051.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

Author information

1
Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía S/N, 18008-Granada, Spain.
2
LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Universités Paris 06, Universités Paris Diderot, Sorbonne Paris Cité, France.
3
Observatório Nacional/MCTIC, Rua General José Cristino 77, Rio de Janeiro CEP 20921-400, Brazil.
4
Federal University of Technology-Paraná (UTFPR/DAFIS), Rua Sete de Setembro 3165, CEP 80230-901 Curitiba, Brazil.
5
Universitäts-Sternwarte München, München, Scheiner Straße 1, D-81679 München, Germany.
6
Max-Planck-Institut für Extraterrestrische Physik, D-85741 Garching, Germany.
7
Dipartimento di Fisica e Astronomia, 'G. Galilei', Università degli Studi di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova, Italy.
8
INAF-Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy.
9
Dipartimento di Fisica, University of Padova, via Marzolo 8, 35131 Padova, Italy.
10
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, H-1121 Budapest, Hungary.
11
Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica, Slovakia.
12
Astronomical Institute, Academy of Sciences of the Czech Republic, Fričova 298, 251 65 Ondřejov Czech Republic.
13
Astronomical Observatory San Marcello Pistoiese CARA Project, San Marcello Pistoiese, Pistoia, Italy.
14
Osservatorio astronomico di Tavolaia, Santa Maria a Monte, Italy.
15
Lajatico Astronomical Centre, Via Mulini a Vento 9 Orciatico, cap 56030 Lajatico, Italy.
16
Osservatorio Astronomico di Monte Agliale, Via Cune Motrone, I-55023 Borgo a Mozzano, Italy.
17
Črni Vrh Observatory, Predgriže 29A, 5274 Črni Vrh nad Idrijo, Slovenia.
18
Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA), Lignan 39, 11020 Nus, Italy.
19
Bayerische Volkssternwarte München, Rosenheimer Straße 145h, D-81671 München, Germany.
20
German Aerospace Center (DLR), Institute of Planetary Research, Rutherfordstraße 2, 12489 Berlin, Germany.
21
Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, PO Box 99, E-03080 Alicante, Spain.
22
Instituto Universitario de Física Aplicada a las Ciencias y la Tecnología, Universidad de Alicante, PO Box 99, E-03080 Alicante, Spain.
23
University of Zagreb, Faculty of Electrical Engineering and Computing, Department of Applied Physics, Unska 3, 10000 Zagreb, Croatia.
24
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
25
European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching bei München, Germany.
26
IMCCE/Observatoire de Paris, 77 Avenue Denfert Rochereau, 75014 Paris, France.
27
Laboratório Interinstitucional de e-Astronomia-LIneA, Rua General José Cristino 77, Rio de Janeiro CEP 20921-400, Brazil.
28
Observatório do Valongo/UFRJ, Ladeira Pedro Antônio 43, Rio de Janeiro CEP 20080-090, Brazil.
29
Observatoire de Genève, CH1290 Sauverny, Switzerland.
30
International Occultation Timing Association-European Section (IOTA-ES) Bartold-Knausstraße 8, D-30459 Hannover, Germany.
31
Facultad de Ciencias Experimentales, Universidad de Huelva, Avenida de las Fuerzas Armadas, 21071 Huelva, Spain.
32
Ege University, Faculty of Science, Department of Physics, 35100 Izmir, Turkey.
33
University of Adiyaman, Department of Physics, 02040 Adiyaman, Turkey.
34
TUBITAK National Observatory (TUG), Akdeniz University Campus, 07058 Antalya, Turkey.
35
Ondokuz Mayis University Observatory, Space Research Center, 55200 Kurupelit, Turkey.
36
Atatürk University, Science Faculty, Department of Physics, 25240 Erzurum, Turkey.
37
Atatürk University, Astrophysics Research and Application Center (ATASAM), 25240 Erzurum, Turkey.
38
Atatürk University, Science Faculty, Department of Astronomy and Astrophysics, 25240 Erzurum, Turkey.
39
Canakkale Onsekiz Mart University, Astrophysics Research Center (ARC) and Ulupınar Observatory (UPO), Canakkale, Turkey.
40
Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, GR-15236 Penteli, Greece.
41
Department of Physics, University of Crete, GR-71003 Heraklion, Greece.
42
INAF-Catania Astrophysical Observatory, Via Santa Sofia 78, I-95123 Catania, Italy.
43
Michael Adrian Observatorium, Astronomie Stiftung Trebur, Fichtenstraße 7, 65468 Trebur, Germany.
44
University of Applied Sciences, Technische Hochschule Mittelhessen, Wilhelm-Leuschner-Straße 13, D-61169 Friedberg, Germany.
45
Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland.
46
Section of Astrophysics, Astronomy and Mechanics, Department of Physics, National and Kapodistrian University of Athens, GR-15784 Athens, Greece.
47
Nunki Observatory, Skiathos Island 37002, Greece.
48
Ellinogermaniki Agogi Observatory, Dimitriou Panagea street, GR-15351 Athens, Greece.
49
Departamento de Física Aplicada I, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Plaza Torres Quevedo 1, 48013 Bilbao, Spain.
50
Observatori Astronòmic de la Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain.
51
Departament d'Astronomia i Astrofísica, Universitat de València, Calle Dr Moliner 50, E-46100 Burjassot, Spain.
52
Centro de Estudios de Física del Cosmos de Aragón, Plaza de San Juan 1, 2ª planta, 44001 Teruel, Spain.
53
Departamento de Astrofísica, Universidad de La Laguna, Avenida Astrofísico Fco Sánchez, 38200 La Laguna, Spain.

Abstract

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

PMID:
29022593
DOI:
10.1038/nature24051

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