Talk abstract details

Ages & compositions of the CoRoT giant planets: a synthesis
M. Havel, T. Guillot


Despite the appetite of the astronomers for small size planets (below 2 Re), giant planets remains of high interest. They are not only
easier to confirm due to their higher mass, but they are also more favorable for more detailed observations (eg. spectroscopy of the atmosphere). That makes them a premium choice for testing evolution models.
With only about two dozen, CoRoT has discovered some of the most interesting and diverse giant planets so far.
After a brief presentation of the tool used for this work, we review the discoveries CoRoT has made. The stellar modeling, together with
transit, spectroscopic and radial velocity data, gives us the eagerly desired physical parameters of each component of the system
(mass, age, radius). On the other hand, the bulk composition of the planet (ie. its heavy elements mass fraction) is inferred from
planet models.
In some cases, there is no models (under reasonable conditions) that can explain the observed mass and radius of the planet. For
instance this is the case for CoRoT-2b, one of the most inflated planet discovered. This problem can usually be resolved by using some
physical arguments that allow to dissipate energy into the deep layer of the planet. But for CoRoT-2b, some other explanations has to be
put forward.
On the other extreme, some planets have a small radius with respect to their mass, and can only be explained by the presence of a
significant mass fraction of heavy elements (assumed to be in a central core). Again, CoRoT has discovered some challenging
planets for which the required core mass cannot be explained by formation models. This is particularly the case of CoRoT-20b.
On another track, thanks to the CoRoT's diversity of systems and their in-depth studies, a number of stars are known to be young
(below 600 Ma). Perhaps due to the activity of these objects, there are some problems to reconcile the models and the observations. CoRoT
has discovered at least three of these interesting systems, and despite their resemblance on many aspects they are yet different.

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