Seminar

Observations found that a significant fraction of solar type stars harbor one or more gas giant planet. According to the core-accretion scenario, the acquisition of their gaseous envelope must be preceded by the formation of super-critical cores with masses ten times or larger than that of the Earth. It is natural to link the formation probability of gas giant planets with the supply of gas and solid in their natal disks. However, the common presence of super Earths suggests that 1) there is no shortage of planetary building-block material, 2) gas giants’ growth barrier is probably associated with whether they can merge into super-critical cores, and 3) super Earths are probably failed cores which did not attain sufficient mass to initiate efficient accretion of gas before it is severely depleted. Here we construct a model based on the hypothesis that protoplanetary embryos migrated extensive before they were assembled into bona fide planets. We construct a Hermit-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. Our simulation results suggest that the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high mass accretion rates whereas systems of super Earths are more likely to emerge out of natal disks with relatively low mass accretion rates.