ISM observation of Phobos reinvestigated: Identification of a mixture of olivine and low-calcium pyroxene

摘要

We reinvestigate the infrared spectral image cube of the Martian satellite Phobos obtained by the Infrared Spectrometer for Mars (ISM) instrument on board PHOBOS 2 using a band detection method based on the wavelet transform. Two absorption bands are identified at 1.04 μm and 1.9 μm. The position and profile of these bands are compatible with a mixture of low-calcium pyroxene and olivine in specific regions on the surface of the satellite. This identification is confirmed by the strong spatial correlation of these two bands, which also corresponds to areas with a lower albedo. Finally, we discuss clues pointing toward possible local hydration of Phobos.