Title: Composition of Extrasolar Giant Planets
Speaker: Tristan Guillot
Abstract: Jupiter, Saturn, Uranus and Neptune are known to be enriched in heavy
elements compared to a mixture of solar composition. The ability to
measure radii of giant planets orbiting other suns should yield a
determination of the global amount of heavy elements present in these
objects. This information would be extremely valuable for validating
and constraining models of planet formation.
However, I will show that this goal requires a detail modeling of the
evolution, and therefore of the atmospheric structure of these
objects. A class of extrasolar giant planets is particularly
interesting in that respect: ``hot Jupiters'' represent about 40% of
the extrasolar planets discovered so far and have the highest
probability of being detected in transit in front of their star. I
will show that in these planets, expected to be in synchronous
rotation with their star, zonal winds are most likely incapable of
efficiently redistributing heat from the day side to the night side,
hence questionning the validity of attempts to model their
atmospheric
structures with a mean stellar insolation.
Reference for students:
Lunch with the students will be on Friday, December 1st at 12:00 in A-101.