Direct detection of Jovian planets around young solar analogs and their atmospheres

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It is not yet clear how frequent and typical our solar system is compared to other planetary systems. Radial velocity searches have been carried out mostly for solar-like early G-type stars, but almost only normal main sequence stars were observed and only close-in massive planets (up to few AU, more than a few Earth masses) can be detected by radial velocity searches.In this new project, we plan to search for massive planets (about half a Jupiter mass and more) around young stars (up to 10 Myrs), which will become solar analog stars once they are on the main sequence. By direct imaging with Adaptive Optics and large telescopes, we can find all massive planets upside of about ~ 10 AU.Once planet candidates are confirmed to be co-moving and orbiting the star, we will take spectra of their atmospheres in the infrared. We will then compare those spectra with model atmospheres such as most recent DRIFT-PHOENIX grid (Witte, Helling & Hauschildt) in order to determine physical parameters such as metallicity, gravity, temperature, radius and, hence, mass.In addition to the search and observation of planets around young stars, we also plan to improve the model atmospheres. The most critical parameter for mass estimation is the gravity. Hence, the model atmospheres have to be improved, so that the precise determination of gravities from both the overall (quasi-) continuum shape and the individual gravity-sensitive lines becomes feasible. For doing so, much better (profile) line data have to be taken into account, coupled to the formation of dust clouds. Also, the parameter space covered in the model grids has to be enlarged (to include less massive and thus cooler planets) and the grid has to be computed with higher parameter resolution for an optimum parameter determination inside the systematic errors.We can use the sample of young massive planets around young solar analog stars to investigate how typical our solar system is and to constrain its formation scenario. This project is a close collaboration between observers and theorists and should also establish a close link between extra-solar planets and solar system planets.