Résumé / Abstract Seminaire_IAP
« Linking the Formation History of Planets with their Spectrum »

Christoph Mordasini
Max-Planck-Institut für Astronomie (Heidelberg, Allemagne)

Based on a planet formation and evolution model and different assumptions about the refractive and volatile composition of the protoplanetary disc gas and planetesimals it might be possible to find the traces of the planetary formation history in the spectrum of an exoplanet. In particular, different migration mechanisms (disk migration versus migration due to the Kozai mechanism or planet-planet scattering) might lead to distinct imprints, which is very interesting from a planet formation point of view. To this end we simulate a planet's formation using a global planet formation model, tracing the material abundances in the accreted material. We then consider the planet's subsequent evolution, evolving the radius, internal and atmospheric structure to a time of interest (an age of several Gyrs when extrasolar planets are typically observed). Using an atmospheric radiative transfer and chemistry model we finally calculate the spectrum of the planets at this age. With this, we can study differences in the spectra resulting from, e.g., different C/O ratios due to different migration histories. It is then discussed whether they can be observed with current and future instruments like JWST. The self-consistent coupling of the planetary bulk composition (yielding the radius) and the spectrum allows to combine observational data from photometric transit observations with follow-up spectroscopy, constraining the theoretical models of planet formation in a novel fashion.
vendredi 9 janvier 2015 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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