Reflectance spectroscopy of diogenite meteorite types from Antarctica and their relationship to asteroids
Spectral reflectance measurements (0.4-2.5μm) of 3 diogenite meteorites found in Antarctica are examined and compared with previous measurements of diogenites to correlate mineralogy and petrography with the spectral characteristics that can also be measured on solar system objects of unknown compos...
Summary: | Spectral reflectance measurements (0.4-2.5μm) of 3 diogenite meteorites found in Antarctica are examined and compared with previous measurements of diogenites to correlate mineralogy and petrography with the spectral characteristics that can also be measured on solar system objects of unknown composition. The Antarctic diogenites have the same spectral characteristics as other diogenites, however there are measurable differences among all diogenite spectra. Analysis of the spectra into sums of gaussian components reveals bands due to spin-forbidden transitions of (Fe)^<2+> ions in pyroxene which are identified for the first time in reflectance spectra of powdered samples. From these laboratory measurements it is shown that spectral reflectance measurements of asteroids and other solar system objects made with the visible CVF spectrometer used for laboratory measurements is capable of providing useful information on their surface composition. The absolute calibration of the relationship between pyroxene chemistry and absorption band position of the 0.9 and 2.0μm bands (ADAMS, J.Geophys. Res., 79,4829,1974) should be recalibrated using new laboratory measurements and for numerically analyzed bands. The trend of the old calibration is not affected. The under-standing of the behavior of reflectance spectra of diogenites gained from this study will be used in a future report to analyze the surface composition of the near-earth asteroid 1915 Quetzalcoatl, which has a diogenite-like reflectance spectrum. |
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