36th DPS Meeting, 8-12 November 2004
Session 15 Icy Satellites
Poster I, Tuesday, November 9, 2004, 4:00-7:00pm, Exhibition Hall 1A

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[15.04] The Infrared Rotational Lightcurve of Phoebe from the Cassini Visual Infrared Mapping Spectrometer (VIMS)

K. Soderlund (Florida Institude of Technology), B. J. Buratti (Jet Propulsion Laboratory), D. P. Simonelli (National Research Council), R. H. Brown (University of Arizona), R. Clark (USGS), D. P. Cruikshank (NASA/Ames), R. Jaumann (DLR), T. McCord (PSI), R. Nelson (Jet Propulsion Laboratory), J. M. Bauer (National Research Council)

Cassini made its first close, targeted flyby of a satellite on June 11, 2004. Phoebe was closely studied by a suite of imagers and spectrometers during this spectacular flyby. A day prior to close encounter, and the day after close encounter, rotational light curves of the satellite were obtained. Since Phoebe is in simple rotation with a period of just over nine hours, these complete lightcurves afford a rough map of the distribution of albedos and possibly volatiles on the surface of the satellite.

Using observations from the Cassini Visual Infrared Mapping Spectrometer (VIMS), we derived rotational light curves in the 2.0 micron water ice absorption band, and in the continuum at 0.9 to 1.4 microns. The satellite exhibits appreciable variation in the strength of the water ice absorption band from one longitude to the next. The strength of the band is correlated with the high-albedo "cliffs" associated with the large impact feature in the northern hemisphere of Phoebe. Our results are consistent with these cliffs being rich in water ice.

Work performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.