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November 16 (4:00PM) in the 2nd Floor Conference Room in Dearborn Speaker: Ed Thommes (CITA) “Saving Giant Planet Cores” In the core accretion model of gas giant planet formation, a large solid core about 10X the Earth's mass forms first, then undergoes runaway accretion of a massive envelope (~100 or more Earth masses) of gas. However, orbital decay due to gravitational interaction with the proto-stellar gas disk poses a big hazard in this model. Core-sized bodies undergo rapid “type I” migration; for typical parameters their migration timescale is much shorter than their accretion timescale. How, then, do growing cores avoid spiraling into the central star before they ever get the chance to become gas giants? Using a global model of planet formation in an evolving gas disk, I will show that a window of opportunity can still exist. The (pre-runaway) formation of atmospheres on the cores contributes significantly to their growth by increasing their planetesimal capture cross-sections. As a result, even in the face of type I migration, a broad range of disk parameters can produce gas giants. |