37th DPS Meeting, 4-9 September 2005
Session 10 Cassini II
Invited, Monday, September 5, 2005, 4:20-5:35pm, Music Concert Hall

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[10.05] UV Spectroscopy of the Saturn System

J. E. Colwell, L. W. Esposito, K. Larsen, A. I. F. Stewart, W. E. McClintock, M. Sremcevic (LASP, Univ. Colorado), D. E. Shemansky, J. T. Hallett (Univ. Southern Calif.), C. J. Hansen, A. R. Hendrix, R. A. West, J. A. Ajello (JPL), W. R. Pryor (Univ. Central Ariz.), Y. L. Yung (Cal. Tech.)

Detailed structure and inhomogeneities are revealed by Cassini UVIS observations of Saturn, Titan, Saturn's icy moons, magnetosphere, and rings. Imaging UV spectroscopy in the EUV and FUV are complemented by high speed photometry of stellar occultations. Water ice is distributed non-uniformly on Phoebe and is present in much smaller amounts in the dark material of Iapetus. Opacity of the A ring is strongly dependent on viewing angle. Multiple observation geometries provide a view of the size, orientation, and spacing of gravitational wakes in the ring. Multiple high resolution occultations have revealed azimuthal structure in the rings while spectroscopy shows a non-uniform distribution of contaminants in the icy rings. A solar occultation of the F ring shows forward-scattering from small particles in that ring. Neutral atomic Oxygen is observed in the region of the E ring in abundances that vary on a timescale of ~10 days and which exceed the Oxygen reservoir in observed E ring icy dust particles. Observations of the atmospheres of Saturn and Titan at multiple phase angles in the FUV provide constraints on particle properties. Stellar occultations by Titan show altitude profiles of six hydrocarbon species in the altitude range 650 to above 1200 km. UVIS obtains images and spectra of Saturn's auroral emissions from molecular and atomic Hydrogen. Recent images show the full auroral oval. The auroral brightness responds to changes in the solar wind. We report on the first year of observations in the Saturn system.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.