title: Evidence of thermal metamorphism on the C, g, B, and f asteroids.
abstract: Reflectance spectra (0.3 to 2.6 micrometers) of 14 C, G, B, and F asteroids and 21 carbonaceous chondrite powders are compared in detail. Only three thermally metamorphosed CM-Cl chondrites that have a weak ultraviolet absorption are shown to have close counterparts among those asteroids. Reflectance spectra of heated Murchison CM2 chondrite are compared with the average C and G type asteroid spectra. Murchison heated at 600 degrees to 1000 degrees C exhibits a similar weak ultraviolet absorption and provides the best analog for those spectra. Comparison of ultraviolet absorption strengths between 160 C, G, B, and F asteroids and carbonaceous chondrites suggests that surface minerals of most of those asteroids are thermally metamorphosed at temperatures around 600 degrees to 1000 degrees C.
authors.forename: T
authors.initials: T
authors.lastname: Hiroi
authors.forename: C M
authors.initials: CM
authors.lastname: Pieters
authors.forename: M E
authors.initials: ME
authors.lastname: Zolensky
authors.forename: M E
authors.initials: ME
authors.lastname: Lipschutz