HR: 0830h
AN: P51B-0454    [PDF]
TI: Ground-based Mid-infrared Observations of Saturn's Rings: Pre-Cassini
AU: * Yanamandra-Fisher, P A
EM: padma@scn.jpl.nasa.gov
AF: Jet Propulsion Laboratory/CIT, MS 169-237 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Fisher, B M
EM: Brendan.M.Fisher@jpl.nasa.gov
AF: Jet Propulsion Laboratory/CIT, MS 169-237 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Orton, G S
EM: Glenn.S.Orton@jpl.nasa.gov
AF: Jet Propulsion Laboratory/CIT, MS 169-237 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Ressler, M E
EM: Micahael.E.Ressler@jpl.nasa.gov
AF: Jet Propulsion Laboratory/CIT, MS 169-237 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Beach-Kimball, B
EM: bbeachkimbal@wesleyan.edu
AF: Wesleyan University, Wesleyan Station, Middletown, CT 06459 United States
AB: We acquired data at the NASA/InfraRed Telescope Facility (IRTF) from 1995 to 2003 with MIRLIN, a mid-infrared camera at several diagnostic wavelengths in the 8- to 24-$\mu$m spectral window. Our observational program has, therefore, covered one fourth of a Saturnian year and followed the progressive march of the rings from their edge-on presentation at the equator in 1995 to their maximum opening, obscuring the northern pole of Saturn. Our specific scientific objectives were to determine the thermal inertia, temperature and opacities of the rings; and thermal asymmetries between the East and West ansae. Our preliminary results indicate that the brightness temperature of the rings peaks near 18 $\mu$m. There exists an asymmetry between the East and West ansae of few (~2) degrees at low and high ring opening angles. This is similar to the near-infrared albedo asymmetry between the ansae and reflectivities at visible wavelengths. Our current efforts are aimed at modelling the ring opacities in the mid-infrared as function of changes in solar elevation angle, inclination and phase angles of the rings. These models will be validated against previous data sets acquired by Voyager and ISO; high resolution spectroscopic data with GEMINI-N; and SIRTF in preparation for Cassini data to be returned from July 2004.
DE: 5465 Rings and dust
DE: 5757 Remote sensing
DE: 5759 Rings and dust
DE: 6265 Planetary rings
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting