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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[45.30] Titan Photochemistry Based on Preliminary Cassini-Huygens Results

E.H. Wilson (Jet Propulsion Laboratory), S.K. Atreya (University of Michigan)

The atmosphere of Titan is characterized by a complex organization of chemical and physical processes that serve to distribute Titan's varied collection of organic compounds. Wilson and Atreya (2004) attempted to describe this system through a photochemical model based on Voyager and ISO observations along with ground-based observations. Recent observations from the Cassini-Huygens mission has further elucidated the nature of Titan's physicochemical system, corroborating some of the predictions of Wilson and Atreya (2004) such as lower levels of ethane condensation, while raising many other questions. For instance, the significant divergence of thermal profiles retrieved by the UVIS, INMS, and HASI instruments has profound implications in the interpretation of the density of the background nitrogen atmosphere, the characterization of the diffusive regime, which helps distribute minor constituents in the upper atmosphere, and the importance of the chemical schemes, which provide sources and sinks for said constituents. Wilson (2005), taking the UVIS-retrieved temperature profile, demonstrated reasonable agreement with UVIS observations including CH4 and good agreement with INMS observations with the exception of CH4, by assuming a medium homopause level similar to that reported in Wilson and Atreya (2004). However, adopting the INMS or the warmer HASI temperature profiles gives different results. These recent Cassini-Huygens observations will be interpreted in the context of our photochemical model results in an effort to understand the processes that govern Titan's constituents.

This research is supported by a grant from the NASA Outer Planets Program.

Wilson, E.H., poster at Titan Workshop, Heraklion, Crete, Greece, 2005. Wilson, E.H. and S.K. Atreya, JGR, 109, E06002, doi:10.1029/2003JE002181, 2004.

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