Interior Structure and Huge Boulder of Itokawa

Abstract

The laser altimetry (LIDAR) aboard the Hayabusa spacecraft measured the surface topography of the asteroid Itokawa and the mass calculated by spacecraft position without orbiting. The mass of Itokawa was estimated as 3.5 x 1010 kg, implying a bulk density of 1.9 g/cm3 and a bulk porosity of -40% when assuming chondritic meteorite composition(density of 3.2 g/cm3) (Abe et al, Science, 2006). In order to investigate the origin of Itokawa, especially for the interior structure and surface characteristics, we will discuss about the principal axis of inertia calculated by Itokawa's shape model and also present a 50m sized biggest bouldar, named 'Yoshinodai', on the surface by using near-infrared and visible spectra.