DPS 2001 meeting, November 2001
Session 49. Outer Planet Satellites
Oral, Chairs: R. Johnson, C. Dumas, Friday, November 30, 2001, 4:30-5:50pm, Regency GH

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[49.04] H2O Chemistry in the Saturnian System

H. T. Smith (Engineering Physics, University of Virginia), V. I. Shematovich (Institute of Astronomy, RAS), R. E. Johnson (Engineering Physics, University of Virginia), S. Jurac (Center for Space Research, MIT)

Based on HST and Voyager observations, the inner Saturnian system is populated by neutral OH and H clouds. These are thought to be residuals of the chemistry of H2O ejected from surfaces of E-ring grains and satellites by UV photons, ions, electrons, and micrometeorites(Jurac et al. Icarus Vol 149, pp 384-396, 2001). The model of H2O chemistry presented here includes the H2O sources, solar UV and magnetospheric electron impacts, losses due to interaction with the Saturnian magnetospheric plasma, and a chemistry network with ion-molecular, neutral-neutral, and molecular ion dissociative recombination reactions. Rates for the chemistry network were updated where possible. The neutral-neutral chemistry, in spite of the energy barriers, was taken into account. That is, although the ambient gas temperature in the inner Saturnian system is low, nonthermal (hot) products of H2O dissociation can result in endothermic reactions such as Hh+ H2O -> OH + H2. This model will allow us to consider in more detail the chemical pathways for OH formation and kinetics, and to better estimate the chemical lifetimes of neutrals in the Saturnian system.

Work supported by NASA's Geology and Geophysics, and Planetary Atmosphere Programs.

The author(s) of this abstract have provided an email address for comments about the abstract: hts4f@virginia.edu

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