Properties of the short period CoRoT-planet population I: Theoretical planetary mass spectra for a population of stars of 0.8 to 2 solar masses and orbital periods of less then 20 days.

Institut fu¨r Theoretische Physik, Universita¨t Bremen , Otto-Hahn-Allee 1, D–28359 Bremen, GermanyReceived December, 27th 2006/ accepted ?ABSTRACTContext.We study the planet populations in the discovery window of the CoRoT-space-telescope scheduled for launch on December27th. We base the prediction on ‘first principles’ calculati ons of planet formation in the framework of the planetesimal hypothesis.Aims.To provide a-priori planetary initial mass functions for confrontation with the CoRoT-planet discoveries in the entire range ofsensitivity of the CoRoT instrument, i.e. for all giant planets and down to terrestrial planet masses.Methods. We construct a comprehensive set of static complete-equilibrium core-envelope protoplanets with detailed equationsofstate and opacity and radiative transfer by convection and radiation. Protoplanets are calculated for host-star masses of 0.8 to 2 solarmasses and orbital periods of 1 to 16 days. We subsequently check the stability of the planetary population by a series of methods.Results.We find the static planetary populations to be stable and thus a plausible ensemble to predict the planetary IMF for orbitalperiods in the specified range.Conclusions.We predict bimodal planetary initial mass functions with shapes depending on orbital period. The two main maximaare around a Jupiter mass and about 50 earth masses. We predict an abundant population of Hot Neptunes and a large population ofplanets that fill the solar-system gap of planetary masses between Neptune and Saturn.Key words. planets:formation – exoplanets – planets: mass – solar syst em:formation – initial mass function