Evidence of hydrated and/or hydroxylated minerals on the surface of asteroid 4 Vesta

Abstract

Asteroid 4 Vesta is thought to be a differentiated object with intact internal structure due to its achondritic surface. In this paper, we report K-L band spectroscopic observations of Vesta. We have detected the presence of a 3-μm absorption feature at about the 1% level on the surface of Vesta at longitudes between 155° and 195°. This result indicates that OH and/or H2O-bearing minerals are present in this region of Vesta; the sources are plausibly fragments of carbonaceous chondrite impactors or solar wind implantation. The detection of 3-μm absorption features from Vesta, regarded as the smallest terrestrial planet, may provide clues to the origin of volatile materials on terrestrial planets. Copyright 2003 by the American Geophysical Union.