Pallas Rpitsbitdt Icarus to Submitted Preprint Foundation
Physical Properties of (2) Pallas✩ Benoˆıt Carrya,b, Christophe Dumasa, Mikko Kaasalainenc, J´erˆome Berthierd, William J. Merlinee, St´ephane Erardb, Al Conradf, Jack D. Drummondg, Daniel Hestrofferd, Marcello Fulchignonib, Thierry Fuscoh aESO, Alonso de C´ordova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile bLESIA, Observatoire de Paris, CNRS, 5 place Jules Janssen, 92190 Meudon Cedex, France cP.O. Box 68 (Gustaf H¨allstr¨omin katu 2b), FI-00014 University of Helsinki, Finland dIMCCE, Observatoire de Paris, CNRS, 77 av. Denfert Rochereau, 75014 Paris, France eSouthwest Research Institute, 1050 Walnut St. # 300, Boulder, CO 80302, U.S.A. fW. M. Keck Observatory, Hawaii, U.S.A. gStarfire Optical Range, Directed Energy Directorate, Air Force Research Laboratory, Kirtland AFB, New Mexico 87117-577, U.S.A. hONERA, BP 72, 92322 Chˆatillon Cedex, France Abstract Ground-based high angular-resolution images of asteroid (2) Pallas at near-infrared wavelengths have been used to determine its physical properties (shape, dimensions, spatial orientation and albedo distribution). We acquired and analyzed adaptive-optics (AO) J/H/K-band observations from Keck II and the Very Large Telescope taken during four Pallas oppositions between 2003 and 2007, with spatial resolution spanning 32–88 km (image scales 13–20 km/pix). We improve our determination of the size, shape, and pole by a novel method that combines our AO data with 51 visual light-curves spanning 34 years of observations as well as archived occultation data. The shape model of Pallas derived here reproduces well both the projected shape of Pallas on the sky (average deviation of edge profile of 0.4 pixel) and light-curve behavior (average deviation of 0.019 mag) at all the epochs considered.
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