A polarimetric study of Asteroid 25143 Itokawa

The near-Earth Asteroid 25143 Itokawa, the target of the Japanese space mission Hayabusa, was observed ill June, 2004 with the Torino photopolarimeter attached at the 2.15 m telescope of the El Leoncito Observatory (Argentina). The degree of linear polarization in five colors was measured over a wide range of phase angles, between 40 degrees and 80 degrees. The data obtained are Sufficient to derive an estimate of the asteroid's albedo of 0.24 +/- 0.01, which is in good agreement with the S-type taxonomic classification of this object. The phase-polarization Curve has been sampled in UBVRI colors, covering a wide range of phase angles that cannot be reached by Earth-based observations of Main Belt asteroids. (c) 2005 Elsevier Inc. All rights reserved.