The changing spectrum of Vesta: Rotationally resolved spectroscopy of pyroxene on the surface

Moderate spectral resolution observations of the 505-nm Fe2+ pyroxene feature in the reflectance spectrum of Vesta were acquired across the complete surface of the asteroid. The feature is consistently centered at 506.54 nm, suggesting an augite (high-calcium) composition. Variations in the equivalent width of the feature correlate with topographically high terrain on Vesta's surface, and could be due to the presence of another material (possibly olivine), or particle size variations, or both. (C) 1998 Academic Press.