HAL : hal-00580822, version 1

arXiv : 1011.5263

DOI : 10.1016/j.icarus.2010.11.016

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Icarus 211, 2 (2011) pp. 1022-1033

Triplicity and Physical Characteristics of Asteroid (216) Kleopatra

Pascal Descamps 1, F. Marchis 1, 2, 3, J. Berthier 1, J. P. Emery 4, G. Duchêne 2, 5, I. De Pater 6, M. H. Wong 7, L. Lim 4, H. B. Hammel 8, F. Vachier 1, P. Wiggins 9, J. -P. Teng-Chuen-Yu 10, A. Peyrot 10, J. Pollock 11, M. Assafin 12, R. Vieira-Martins 1, 13, J. I. B. Camargo 13, 14, F. Braga-Ribas 12, 13, B. Macomber 3

(02/2011)

To take full advantage of the September 2008 opposition passage of the M-type asteroid (216) Kleopatra, we have used near-infrared adaptive optics (AO) imaging with the W.M. Keck II telescope to capture unprecedented high resolution images of this unusual asteroid. Our AO observations with the W.M. Keck II telescope, combined with Spitzer/IRS spectroscopic observations and past stellar occultations, confirm the value of its IRAS radiometric radius of 67.5 km as well as its dog-bone shape suggested by earlier radar observations. Our Keck AO observations revealed the presence of two small satellites in orbit about Kleopatra (see Marchis et al., 2008). Accurate measurements of the satellite orbits over a full month enabled us to determine the total mass of the system to be 4.64+/-0.02 10^18 Kg. This translates into a bulk density of 3.6 +/-0.4 g/cm3, which implies a macroscopic porosity for Kleopatra of ~ 30-50%, typical of a rubble-pile asteroid. From these physical characteristics we measured its specific angular momentum, very close to that of a spinning equilibrium dumbbell.

1 :	Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE)
	CNRS : UMR8028 – INSU – Observatoire de Paris – Université Pierre et Marie Curie [UPMC] - Paris VI – Université Lille I - Sciences et technologies
2 :	Department of Astronomy
	University of California, Berkeley
3 :	SETI Institute
	SETI Institute
4 :	Department of Earth and Planetary Sciences
	University of Tennessee, Knoxville
5 :	Laboratoire d'Astrophysique de Grenoble (LAOG)
	Université Joseph Fourier - Grenoble I
6 :	Astronomy Department, University of California at Berkeley
	University of California, Berkeley
7 :	Department of Astronomy
	University of California, Berkeley
8 :	Space Science Institute
	Space Science Institute
9 :	Wiggins Observatory
	Wiggins Observatory
10 :	Makes Observatory
	Makes Observatory
11 :	Department of Physics and Astronomy
	Appalachian State University
12 :	Observatório do Valongo/UFRJ
	Observatório do Valongo
13 :	Observatório Nacional/MCT
	Observatório Nacional/MCT
14 :	Observatório do Valongo
	Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio

Domaine

:

Physique/Astrophysique/Planétologie et astrophysique de la terre Planète et Univers/Astrophysique/Planétologie et astrophysique de la terre

Mots Clés : Asteroids – Satellites of asteroids – Adaptive optics – Photometry – Orbit determination

hal-00580822, version 1

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Contributeur : Camille Baron <>

Soumis le : Mardi 29 Mars 2011, 13:07:01

Dernière modification le : Mercredi 27 Avril 2011, 17:44:08