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N. Iro, B. Bézard (LESIA, Obs. Paris-Meudon), T. Guillot (CASSINI, Obs. Côte d'Azur)
The study of the light curve of the transiting planet HD209458b provided for the first time an accurate measurement of its mass and its radius. It represents a strong constraint on evolutionary models of Pegasi planets. These planets should be in synchronous rotation, and as shown by Showman & Guillot (2002), should have a significant day/night temperature variation and zonal winds with velocities of about 1 km/s in the photosphere. These estimations however rely on simplified assumptions on the radiative timescale.
We present a time-dependent radiative equilibrium model for the transiting planet HD209458b. Our model allows us to calculate the characteristic radiative timescale as a function of depth and, by mimicking atmospheric circulation as a slow solid body rotation, the global temperature map as a function of longitude. We predict day-night temperature variation of about 600K at the 0.1 bar pressure level for a rotation rate of 1 km/s, in relatively good agreement with variation of about 600K at the 0.1 bar pressure level for a rotation rate of 1 km/s, in relatively good agreement with the predictions by Showman & Guillot (2002).
The author(s) of this abstract have provided an email address for comments about the abstract: nicolas.iro@obspm.fr
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.