Ground-based lightcurve observation campaign of (25143) Itokawa between 2001 and 2004

Abstract

The asteroid (25143) Itokawa is a target object of the Japanese sample return mission, HAYABUSA. We have observed Itokawa in optical wave- length (R-band) with the 1.05-m Schmidt telescope at the Kiso Observatory, the 2.24-m telescope of University of Hawaii, and the 1.05-m telescope at the Misato Observatory since 2001. From the analysis of the data, we present the relationship between brightness and the solar phase angle, 6.9 to 87.8 deg. We obtained the absolute magnitude H_R(0) = 19.09+-0.37, and the slope parameter G_R = 0.25 +- 0.29. The rotational period of Itokawa is 12.1324 +- 0.0001 hours.