TY - JOUR
T1 - Triplicity and physical characteristics of Asteroid (216) Kleopatra
AU - Descamps, P.
AU - Marchis, F.
AU - Berthier, J.
AU - Emery, J. P.
AU - Duchêne, G.
AU - de Pater, I.
AU - Wong, M. H.
AU - Lim, L.
AU - Hammel, H. B.
AU - Vachier, F.
AU - Wiggins, P.
AU - Teng-Chuen-Yu, J. P.
AU - Peyrot, A.
AU - Pollock, J.
AU - Assafin, M.
AU - Vieira-Martins, R.
AU - Camargo, J. I.B.
AU - Braga-Ribas, F.
AU - Macomber, B.
N1 - Funding Information:
These data were obtained with the W.M. Keck Observatory, which is operated by the California Institute of Technology, the University of California, Berkeley and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, none of the observations presented would have been possible. FMA was supported by the National Science Foundation under award number AAG-0807468.
PY - 2011/2
Y1 - 2011/2
N2 - 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 67.5km 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, F. et al. [2008a]. (3749) Balam. In: Green, D.W.E. (Ed.), IAU Circ. 8928; Marchis, F., Descamps, P., Berthier, J., Emery, J.P. [2008b]. S/2008 ((216)) 1 and S/2008 ((216)) 2. In: Green, D.W.E. (Ed.), IAU Circ. 8980). Accurate measurements of the satellite orbits over a full month enabled us to determine the total mass of the system to be 4.64±0.02×1018kg. This translates into a bulk density of 3.6±0.4g/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.
AB - 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 67.5km 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, F. et al. [2008a]. (3749) Balam. In: Green, D.W.E. (Ed.), IAU Circ. 8928; Marchis, F., Descamps, P., Berthier, J., Emery, J.P. [2008b]. S/2008 ((216)) 1 and S/2008 ((216)) 2. In: Green, D.W.E. (Ed.), IAU Circ. 8980). Accurate measurements of the satellite orbits over a full month enabled us to determine the total mass of the system to be 4.64±0.02×1018kg. This translates into a bulk density of 3.6±0.4g/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.
KW - Adaptive optics
KW - Asteroids
KW - Orbit determination
KW - Photometry
KW - Satellites of asteroids
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U2 - 10.1016/j.icarus.2010.11.016
DO - 10.1016/j.icarus.2010.11.016
M3 - Article
AN - SCOPUS:79151485433
SN - 0019-1035
VL - 211
SP - 1022
EP - 1033
JO - Icarus
JF - Icarus
IS - 2
ER -