Constraints on the Compositions of Phobos and Deimos from Mineral AbsorptionsThe compositions of Phobos and Deimos have remained controversial despite multiple Earth- and space-based observations acquired during the last 40 years. Phobos is composed of at least two spectral units that are both dark yet distinct at visible to near infrared wavelenghts; a spectrally red-sloped "red" unit covers most of the moon and a less red-sloped "blue" unit is present in the ejecta of the approximately 9-km diameter impact crater Stickney [1,2]. Deimos is similar spectrally to Phobos' "red" unit [2]. Here we report results from mapping mineral absorptions on Phobos and Deimos using visible/near infrared observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). We find evidence for an absorption feature at 0.65 m in the Phobos red unit and Deimos that is reproducible in observations from other instruments. The phase responsible is uncertain but may be a Fe-bearing phyllosilicate and/or graphite, consistent with the notion that Phobos and Deimos have compositions similar to CM carbonaceous chondrites [3].
Document ID
20130009708
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Fraeman, A. A. (Washington Univ. Saint Louis, MO, United States)
Murchie, S. L. (Johns Hopkins Univ. Laurel, MD, United States)
Arvidson, R. E. (Washington Univ. Saint Louis, MO, United States)
Rivkin, A. S. (Johns Hopkins Univ. Laurel, MD, United States)
Morris, R. V. (NASA Johnson Space Center Houston, TX, United States)