HR: 1340h
AN: P33C-0262    [Abstracts]
TI: The High Altitude Sunlit Titan Ionosphere
AU: * Liu, X
EM: xianming@usc.edu
AF: University of Southern California, Aerospace and Mechanial Engineering 854 Downey Way, RRB 101 , Los Angeles, CA 90089-1191 United States
AU: Shemansky, D E
EM: shemansk@spock.usc.edu
AF: University of Southern California, Aerospace and Mechanial Engineering 854 Downey Way, RRB 101 , Los Angeles, CA 90089-1191 United States
AU: Hallett, J T
EM: jtew@usc.edu
AF: University of Southern California, Aerospace and Mechanial Engineering 854 Downey Way, RRB 101 , Los Angeles, CA 90089-1191 United States
AB: Cassini UVIS EUV and FUV spectrograph observations of high altitude sunlit Titan atmosphere emission show measurable emission at and above the exobase in electron excited nitrogen. The observations include emission from the N₂ c_{4}^' (0,0) and other bands, NI, and NII in the EUV, with the N2 LBH system NI, HI and CI in the FUV. The emission properties indicate the top of the atmosphere has a developed ionosphere maintained by deposition of soft magnetospheric electrons. Comparison of the sub-solar equatorial region at encounter T0 with the sunlit polar high altitude emission obtained at TA will be described through application of a nitrogen physical chemistry model fit to the data. At the altitudes examined here, extinction by CH4 is not measurable. Estimates of [N]/[N2] partioning has high as 0.07 have been obtained. The inferred dissociation rates will be used to provide a loss rate into the magnetosphere for atomic nitrogen.}
DE: 5405 Atmospheres (0343, 1060)
DE: 5408 Aurorae and airglow
DE: 5410 Composition (1060, 3672)
DE: 5435 Ionospheres (2459)
DE: 6281 Titan
SC: Planetary Sciences [P]
MN: Fall Meeting 2005