37th DPS Meeting, 4-9 September 2005
Session 45 Titan's Atmosphere
Poster, Wednesday, September 7, 2005, 6:00-7:15pm, Music Recital Room

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[45.08] Titan's Oxygen compound distributions and condensate characteristics from Cassini/CIRS observations

R. de Kok, P.G.J. Irwin, N.A. Teanby, L. Fletcher, S.B. Calcutt, C. Howett, F.W. Taylor, N.E. Bowles (University of Oxford), Cassini CIRS Team

The Cassini/CIRS instrument has measured Titan's infrared spectrum many times since its arrival at Saturn in July 2004. Observations were made both in nadir and in limb geometry, at a wide range of latitudes and altitudes.

Using nadir and limb data with the highest spectral resolution obtainable by CIRS (0.5 cm-1), the stratospheric emission of carbon dioxide at 667 cm-1 was analysed. Results of this analysis include the variations of the CO2 concentration with latitude, and the variation with altitude. The latter is critical for understanding the oxygen chemistry in Titan's atmosphere and can constrain the nature of Titan's oxygen source. The abundance of CO was also determined and an upper limit was set for the H2O abundance.

CIRS has the capability to measure, for the first time, the spectral region between 10-200 cm-1. This region is mainly dominated by collision induced absorption and includes the rotational lines of e.g. CH4, HCN and CO. In this region, at least two broad spectral features were also identified, possibly caused by condensates. CIRS data with low spectral resolution (15 cm-1) was used to obtain dependences with latitude and altitude of these features, therefore constraining their possible sources.

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