Observing and modeling young transiting planets

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It is still not clear how massive gas giant planets form, whether by direct gravitational collapse (i.e. contracting) or first by dust coagulation and slow growth of a solid core (growing), then accreting an atmosphere; or whether both paths are possible. One way to find out is to measure radii and compositions of young forming planets. This is possible currently only with the planet transit technique, where the radii and masses (together with radial velocity observations) can be determined. Among the many transiting planets know so far, none (but 2) is younger than some 100 Myr. We aim to find young forming planets and determine their radii and masses, so that characteristics of their formation process can be revealed.As second part of the project we will perform theoretical modeling of the inner composition of those extra-solar (young) giant planets. We consider the atmosphere of the planet as well, its coupling to the stellar radiation and to the deeper interior. New equation of state data have been derived at the U Rostock by performing extensive finite-temperature density functional theory molecular dynamics (DFT-MD) simulations for the planetary materials hydrogen, helium, water, ammonia, and MgO for a wide range of pressures and temperatures. Based on this ab initio equation of state data we model the interior of gas giant planets accounting for three major parts: solid core, fluid layer(s) and a gas atmosphere.Using the detected observables (e.g. total mass and radius) as constraints for the models we can predict, e.g., the mass of a solid core, the total mass of metals in the planet and the metal fraction in the layer(s). Another result is the mass and extent of the atmosphere. The expected results would enable us to discriminate between different formation scenarios and, thus, lead to a better understanding of planetary formation processes and their interior structure in general.