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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[18.09] Photochemistry in the Atmosphere of HD 209458b

M.-C. Liang, C. D. Parkinson, Y Yung (Caltech), S Seager (Carnegie)

We have developed a 1-dimensional model to study the chemistry in the upper atmosphere of this extrasolar “hot jupiter". The 3 most abundant elements (other than He), as well as 4 parent molecules are included in this model, viz., H, C, O, H2, CO, H2O, and CH4. The higher temperatures (~ 1000 K) and higher stellar irradiance strongly enhance and modify the chemical reaction rates in this atmosphere. The main results are that (a) the production of atomic hydrogen in the atmosphere is mainly driven by H2O photolysis and reaction of OH with H2, and is not sensitive to the exact abundances of CO, H2O, and CH4, and (b) H2O and CH4 can be produced via the photolysis of CO followed by the reactions with H2.

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