HR: 13:45h
AN: P13A-02    [Abstracts]
TI: Cassini UVIS Results from Saturn, Titan, Icy Satellites and Rings
AU: * Esposito, L W
EM: larry.esposito@lasp.colorado.edu
AF: LASP, University of Colorado 392 UCB, Boulder, CO 80309-0392 United States
AU: Colwell, J E
EM: Josh.Colwell@lasp.colorado.edu
AF: LASP, University of Colorado 392 UCB, Boulder, CO 80309-0392 United States
AU: Hansen, C J
EM: Candice.J.Hansen@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Hallett, J T
EM: jtew@usc.edu
AF: Dept of Aerospace Engineering, University of Southern California 854 W 36 Place, Los Angeles, CA 90089 United States
AU: Hendrix, A R
EM: arh@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Larsen, K
EM: kris.larsen@lasp.colorado.edu
AF: LASP, University of Colorado 392 UCB, Boulder, CO 80309-0392 United States
AU: McClintock, W E
EM: Bill.McClintock@lasp.colorado.edu
AF: LASP, University of Colorado 392 UCB, Boulder, CO 80309-0392 United States
AU: Pryor, W R
EM: Wayne_Pryor@centralaz.edu
AF: Central Arizona College, 8170 N. Overfield Road, Coolidge, AZ 85228 United States
AU: Shemansky, D E
EM: dons@hippolyta.usc.edu
AF: Dept of Aerospace Engineering, University of Southern California 854 W 36 Place, Los Angeles, CA 90089 United States
AU: Stewart, A I
EM: Ian.Stewart@lasp.colorado.edu
AF: LASP, University of Colorado 392 UCB, Boulder, CO 80309-0392 United States
AU: West, R A
EM: raw@west.jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: Dynamic interactions between neutrals, ions, rings, moons and meteoroids produce a highly structured and time variable Saturn system. UVIS has detected neutral oxygen, which dominates the Saturn inner magnetosphere, in contrast to Jupiter. The O is probably the product of water physical chemistry, and derived ultimately from water ice. Observed fluctuations indicate close interactions with plasma sources. Stochastic events in the E ring may be the ultimate source. Saturn's aurora varies by at least a factor of 4, associated with solar wind shocks and kilometric radio emission. Prior to Cassini's orbit insertion at Saturn, UVIS detected the spectral signature of water ice on Phoebe and in Saturn's rings, mixed non-uniformly with darker constituents. Recent observations of Enceladus, Tethys, Dione, Rhea and Iapetus allow us to begin to compare the surfaces of Saturn's icy satellites. Titan emissions show atomic, molecular and ionized nitrogen. Haze layers have been detected in reflected light from Titan's atmosphere, and show a difference in structure between the equator and the poles. The spacecraft made a close flyby of Titan on 13 December 2004 and stellar occultations of alpha Vir (Spica) and lambda Sco were observed. The occultation probed the night side of Titan in the southern hemisphere. Six hydrocarbon species were identified, CH4, C2H2, C2H4, C2H6, HCN, and C4H2. The UVIS derived temperature at the top of the atmosphere agrees with the results of the Ion Neutral Mass Spectrometer. The transition from convective to diffusive separation occurs between 800 km and 1100 km.Additionally, we find a previously unobserved 80 km layer at 1350 km, showing abundances of CH4 and C2H4 a factor of ~5 above the ambient underlying distribution.
DE: 6265 Planetary rings
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2005 Joint Assembly