Phobos surface composition: clues from laboratory emissivity measurements and MGS-TES spectral data

Abstract

The debate about the composition of the Martian moon Phobos is still open, even if it has been observed both from Earth and from spacecraft orbiting Mars. In this work we used the linear deconvolution technique on thermal infrared spectra acquired by Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) [1] to investigate its surface composition. The preliminary results here shown seem to be indicative of a large abundance of phyllosilicates (e.g. biotite), with small amounts of other materials, mainly olivines. In particular the grain sizes involved should be very fines, with particle diameter less than 25 micrometerm. However, since the linear deconvolution can be considered high efficient only for large particles, further investigations, involving laboratory spectra of mixtures of phyllosilicates and olivines, have to be performed.