题  目：Growth and Migration of Embryos in Protoplanetary Disks

　　报告人：刘倍贝（北京大学）

　　摘  要：Observations indicate that 15-20% of solar-type stars harbor at least one gas giant planet, and nearly half of them host one or more super Earths with periods up to 100 days. The common existence of super Earths but lack of gas giants may imply that 1) there is no shortage of planetary building-block materials, 2) the gas giants growth barrier is probably associated with whether they can merge into critical mass (Mc≃ 10M⊕) cores. Thus, the asssemblage of critical mass cores is a crucial step in the formation of gas giant planets. We construct a Hermite-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. This code is used to simulate the convergent migration of embryos, and their close encounters and coagulation. The progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high (~10−7 M⊙ yr−1) mass accretion rates, whereas systems of super Earths (failed cores) are more likely to emerge out of natal disks with modest mass accretion rates, due to the mean motion resonance barrier and retention efficiency.

　　时  间：2015年1月7日上午10:00

　　地  点：紫台517会议室

　　联系人：董瑶（83332059）

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