HR: 17:50h
AN: P44A-07    [Abstracts]
TI: Cassini radio occultations of Titan's ionosphere
AU: * Kliore, A J
EM: akliore@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive M.S. 238-343, Pasadena, CA 91103, United States
AU: Nagy, A F
AF: University of Michigan, 2455 Hayward Ave, Ann Arbor, MI 48109, United States
AU: Flasar, F M
AF: NASA Goddard Space Flight Center, Code 693, Greenbelt, MD 20771, United States
AU: Schinder, P J
AF: Cornell University, 1034 Karen St, Boalsburg, PA 16827, United States
AU: French, R G
AF: Wellesley College, Astronomy Dept, Wellesley, MA 02181, United States
AU: Marouf, E A
AF: San Jose State University, One Washington Square, San Jose, CA 95192, United States
AU: Rappaport, N J
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive M.S. 238-343, Pasadena, CA 91103, United States
AU: Anabtawi, A
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive M.S. 238-343, Pasadena, CA 91103, United States
AU: McGhee, C A
AF: Wellesley College, Astronomy Dept, Wellesley, MA 02181, United States
AB: We report results on Titan's ionosphere from the Cassini radio occultation of March 26, 2007 (T27), as well as those of March 19, 2006 (T12), and May 20,2006 (T14) . The 2006 occultations occurred at low Southern latitudes of 14.7S, 36.2S, 19.8S, and 21.9S. The 2007 occultation was nearly polar, at latitudes of 81S and 59N. The solar zenith angles for all occultations were near the terminator, ranging from 85 to 95 deg. The ionosphere peak was observed to lie close to an altitude of 1200 km, and the observed peak densities ranged from about 1.2 to 2.0x103 cm-3, which is in fairly good agreement with other Cassini observations and the previous Voyager radio occultation results. Radio occultation observations of the Titan ionosphere are difficult because of its low density and small size, and it was facilitated by the unprecedented Cassini radio science system, which has three frequencies that can operate simultaneously: S-band (2.3 GHz), X-band (8.4 GHz), and Ka-band (32 GHz). In particular, Ka-band hads never been used before to probe Titan's ionosphere, and the signal-to-noise ratios at all frequencies of 42, 54, and 48 dB-Hz., respectively, have never before been achieved.
DE: 2459 Planetary ionospheres (5435, 5729, 6026)
DE: 5435 Ionospheres (2459)
DE: 6024 Interiors (8147)
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly