Near-Infrared Mapping and Physical Properties of the Dwarf-Planet Ceres

Authors: Benoit Carry, Christophe Dumas, Marcello Fulchignoni, William J. Merline, Jerome Berthier, Daniel Hestroffer, Thierry Fusco, Peter Tamblyn

(Submitted on 7 Nov 2007)

Abstract: We study the physical characteristics (shape, dimensions, spin axis direction, albedo maps, mineralogy) of the dwarf-planet Ceres based on high-angular resolution near-infrared observations. We analyze adaptive optics J/H/K imaging observations of Ceres performed at Keck II Observatory in September 2002 with an equivalent spatial resolution of ~50 km. The spectral behavior of the main geological features present on Ceres is compared with laboratory samples.

Ceres' shape can be described by an oblate spheroid (a = b = 479.7 +/- 2.3 km, c = 444.4 +/- 2.1 km) with EQJ2000.0 spin vector coordinates RA = 288 +/- 5 deg. and DEC = +66 +/- 5 deg. Ceres sidereal period is measured to be 9.0741 +/- 0.0001 h. We image surface features with diameters in the 50-180 km range and an albedo contrast of ~6% with respect to the average Ceres albedo. The spectral behavior of the brightest regions on Ceres is consistent with phyllosilicates and carbonate compounds. Darker isolated regions could be related to the presence of frost.

Comments: 11 pages, 8 Postscript figures, Accepted for publication in A&A

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0711.1152v1 [astro-ph]

Submission history

From: Beno\^it Carry [view email]

[v1] Wed, 7 Nov 2007 20:52:35 GMT (930kb)

http://arxiv.org/abs/0711.1152