Ca and Fe abundance on the surface of asteroid Itokawa constrained by Hayabusa X-ray fluorescence spectrometer

Abstract

XRS (x-ray spectrometer) onboard Hayabusa has observed x-ray fluorescence from near-Earth asteroid 25143 Itokawa to determine major elemental composition. Okada et al. (2006) reported average elemental mass ratios of Mg/Si = 0.78 + - 0.09 and Al/Si = 0.07 + - 0.03. In this study, we attempted to estimate upper limits of Ca and Fe. To discussion about abundance of Ca and Fe, we need to integrate data longer time, fallowing the result of numerical simulation. In this poster, we report a result and the method of the analyses.