Hybrid Mechanisms for Gas/Ice Giant Planet Formation
نویسنده
چکیده
The effects of gas pressure gradients on the motion of solid grains in the solar nebula substantially enhances the efficiency of forming protoplanetary cores in the standard core accretion model in ’hybrid’ scenarios for gas/ice giant planet formation. Such a scenario is ’migration-enhanced’ core accretion which results from Epstein-drag induced inward radial migration of mm-sized grains needed to build up a population of 1 km planetesimals. Solid/gas ratios can be enhanced by nearly ∼ 10× over those in Minimum Mass Solar Nebula (MMSN) in the outer solar nebula (a > 20 AU), increasing the oligarchic core masses and decreasing formation timescales for protoplanetary cores. A 10 M⊕ core can form on ∼ 10 years timescales at 15 25 AU compared to ∼ 10 year timescales in the standard model, alleviating the major problem plaguing the core accretion model for gas/ice giant planet formation. Subject headings: planet formation: general — planet formation: core accretion, planet formation: gravitational instability planet formation: hybrid model
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