The Division for Planetary Sciences of the American Astronomical Society awards the 2006 Harold C. Urey Prize for outstanding achievement in planetary research by a young scientist to Tristan Guillot, a Charge de Recherche of the CNRS at the Observatoire de la Cote d’Azur, in Nice, France. Guillot is a recognized expert in radiative transfer and its application to the internal structures of giant planets, both inside and outside our solar system. He has developed unique insights on how to properly treat the influence of strong stellar irradiation on the evolution of the deep convective zones of giant planets, discovering that a thickening radiative zone forms at the surface as the planet’s interior cools. With colleagues, he correctly predicted that hydrogen-rich exoplanets should have higher entropies than our own gas giants, and therefore larger radii. His doctoral work showed that hydrogen-helium alone does not produce sufficient opacity to maintain Jupiter and Saturn in convective equilibrium at kilobar pressure levels. This has important implications for these planets’ history and internal structure and opens a potential role for other opacity sources. Guillot’s synthesis of Galileo probe measurements with interior equations of state has determined that Jupiter’s core is much less massive than that of Saturn and that a substantial amount of heavy elements are retained in the envelope of Jupiter — the most definitive analysis of these important quantities to date. He has also contributed to the fields of brown dwarfs, giant planet formation, and the dynamics of atmospheric flow on tidally-synchronized gas giants. He has worked as well to advance planetary science in his native France, and on the upcoming COROT and JUNO missions.

As a young scientist demonstrating outstanding achievement with great potential for future success and scientific leadership, the Division for Planetary Sciences is pleased to award the 2006 Harold C. Urey Prize to Tristan Guillot.

Observatoire de La Cote D’ Azur
Email:guillot@obs-nice.fr
http://www.obs-nice.fr/guillot
Work Phone:33-4-92003047
Fax:33-4-92003121
Address: Lab. Cassini
BP 4229
Nice, Cedex 4 06304
France