OLIVINES ON VESTA-LIKE ASTEROIDS

Reflectance spectra of some Vesta-like asteroids contain a faint isolated absorption band near 600 nm. Center position of this band varies in the range of ~ 590 – 640 nm in various spectra of the vestoids. Looking over reflectance spectra of orthopyroxenes and achondrites, we found that some spectra of enstatites, bronzites, hypersthenes, and HED meteorites do contain a faint feature centered in the range of ~ 590 – 620 nm. At the same time, we could not find any absorptions centered longward of 620 nm in the spectra of the specified sample. One of the probable cause of origin of this feature in the vestoid spectra is spectral contribution of olivine component of the vestoid rocks. Considering this supposition, we did not overlook, of course, the conclusion about low abundance of the olivine on vestoid surfaces [1]. It is known the reflectance olivine spectra contain a wide absorption near 600 nm. We estimated center position of this band for the olivine spectra obtained in [2].