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S. Perrier (Service d�A�ronomie du CNRS, BP3, 91371 Verrieres-le-Buisson, France), A.S. Stern (Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302, USA), J.L. Bertaux (Service d�A�ronomie du CNRS, BP3, 91371 Verrieres-le-Buisson, France)
The eccentric orbit of Mars Express allows some close encounters with PHOBOS. Four observations were organized up to August 11, 2004. The spacecraft was put in a fixed inertial position, and Phobos was scanned from the orbital motion, crossing the slit of SPICAM UV imaging spectrometer in a few seconds. The distance was from 150 to 1900 km. Along the slit, five FOV of 10 x 1.3 arcmin each recorded the UV spectrum (110-310 nm, resolution 1.5 nm) of scattered solar light, resulting in 30 to 50 independent UV spectra at each encounter, and giving an unprecedented spatial resolution in UV. From the absolute calibration of SPICAM with star observations, the albedo may be determined as a function of wavelength and geography. Albedo markings were search for. The UV color (wavelength trend in the range 200-320 nm) was determined.Comparisons with previous measurements (in particular HST) will be discussed, with potential implications for mineralogy of Phobos.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.