DPS 35th Meeting, 1-6 September 2003
Session 18. Extra Solar Planets II
Poster, Highlighted on, Wednesday, September 3, 2003, 3:00-5:30pm, Sierra Ballroom I-II

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[18.06] The Water Cycle and Habitability of Earth-like Planets

E. Gaidos (University of Hawaii)

Earth's composition and habitability are the result of cosmochemical conditions that need not hold elsewhere. Compositional variations in protostellar nebulae and differences in planetary formation and evolution may have produced a diversity of silicate-metal planets that exceeds that of the Solar System. Differences in composition and mineralogy will manifest themselves as variations in a planetary mantle's rheology, melting properties, and dynamics. The Earth's geologic water cycle is coupled to the mantle through partition of water into magmas, release at divergent margins and hotspots, and the subduction of hydrated oceanic lithosphere at convergent margins. The rate of the reduction of water to hydrogen in mantle material and its escape to space depends on the mantle oxidation state. Variation in these fluxes creates the possibility of dessication of the surface or dehydration of the mantle, with profound implications for habitability. Results of modeling of these processes that illustrate possible outcomes are presented.

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.