SELECTIVE VOLATILE DEPLETION ON THE SURFACE OF ASTEROIDS PROCEEDINGS OF THE ASTEROIDS, COMETS AND METEORS CONFERENCE

摘要

Data from the x-ray and γ-ray spectrometers onboard the Near Earth Asteroid Rendezvous (NEAR) Spacecraft were used to constrain the chemical and mineralogical composition of asteroid Eros. The S/Si ratio (0.014 +- 0.017) is consistent with complete loss of all S from the surface, while all other volatiles measured appear to be chondritic in abundance. We investigate space weathering mechanisms to determine the extent to which volatiles, especially S, can be preferentially lost from the surface regolith. Using impact data for Al projectiles onto enstatite, we find that the vaporization rate for sulfur is ～10 times faster than that for the bulk of the regolith.