DPS 35th Meeting, 1-6 September 2003
Session 22. Asteroid Physical Studies I
Oral, Chairs: Clark and R.P. Binzel, Thursday, September 4, 2003, 10:30am-12:00noon, DeAnza III

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[22.09] Multi-color adaptive optics imaging of asteroid 1 Ceres

C. Dumas (Jet Propulsion Laboratory, Caltech), W. J. Merline (Southwest Research Institute), R. P. Binzel (Massachusetts Institute of Technology), R. H. Brown (University of Arizona), T. Fusco (Onera - France), R. J. Terrile (Jet Propulsion Laboratory, Caltech)

We report Adaptive Optics (AO) J/H/K-band imaging results obtained on asteroid 1 Ceres (mean physical diameter of ~950 km) with the Keck-II telescope and its near-infrared camera NIRC2 (10 milliarcsecond/pixel). The asteroid (rotation period of 9.075 h) was observed repeatedly in September 2002 with a rotational sampling of ~ 10 deg. Its nearly equator-on geometry permitted imaging of most of its surface. The angular resolution provided by Keck-AO at H-band is equivalent to 60 km at the distance of Ceres, which results in spatialy sampling its apparent disk (0.66" diameter) with more than 200 resolution elements (~16 resolution elements, or 64 pixels, along the diameter). Image restoration (Mistral deconvolution) has been applied to the data-set. The deconvolved images reveal two large albedo features (~130 km diameter) that can be followed as they rotate with the asteroid. We report the preliminary results obtained on the analysis of its shape, direction of rotation axis, and location of its main geological marks. Ultimately, this data set will provide a complete 3-D model for Ceres, a precise determination of the direction of its spin axis, as well as multi-color albedo maps of the surface of the largest main-belt asteroid.

The author(s) of this abstract have provided an email address for comments about the abstract: Christophe.Dumas@jpl.nasa.gov

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.