Optical spectrometry of meteorites. IV - Comparative analysis of the spectral properties of achondrites and ordinary chondrites

The spectral properties of achondrites and ordinary chondrites are analyzed and compared. Based on the presence or absence of the characteristic Fe(2+) and Cr(3+) absorption bands in their spectra, a preliminary spectral classification is proposed for luminous stony meteorites. The effect that reduced metal has on these spectra is discussed as well as the constraints inherent to optical spectrometry in the remote sensing of asteroidal surface composition. A photometric system consisting of four filters is recommended for the scanning of differentiated and/or undifferentiated matter present on faint asteroids. The wavelengths most effective for these light-filters are 0.4, 0.56, 0.65, and 0.75 microns.