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Résumé |
In the past few years, the research on extrasolar planets has shifted
from the discovery of these objects to their physical characterization.
This means that for the first time, the intrinsic luminosity, the
internal structure, and the atmospheric composition of planets outside
of the Solar System were measured. In my talk I will show how these
observations can be used to better understand the physics of planet
formation. I will address two different aspects: first, it is shown how
observations of the intrinsic luminosity emitted by young giant planets
constrains the physics of the accretion shock which occurs when a
forming gas giant planet rapidly accretes gas from the protoplanetary
nebula. Second, it is discussed how the amount of hydrogen/helium
contained in an exoplanet (that can be derived from the combined
measurement of the mass and radius) is an indicator of magnitude of the
opacity in the atmosphere of forming protoplanet. This opacity is mainly
due to micrometer sized grains that are suspended in the gas. Therefore,
this observation allows to understand the dynamics of the grains like
their growth and settling, which can be described with an analytical model. |
