Migration and Growth of Protoplanetary Embryos II: Emergence of Proto-Gas-Giants Cores versus Super Earths' Progenitor

Abstract

Nearly $15-20$ of solar type stars contain 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, a much richer population 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 extensively before they were assembled into bona fide 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 1) the convergent migration of embryos, and 2) their close encounters and coagulation. Around the progenitors of solar-type stars, the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high ($\gtrsim 10^{-7}{M}_{\odot }$ 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.

12 pages, 5 figures, 1 table. Accepted for publication in ApJ

References in corpus (9)

• Three regimes of extrasolar planets inferred from host star metallicities
• Analytical protostellar disk models 1: the effect of internal dissipation and surface irradiation on the structure of disks and the location of the snow line around Sun-like stars
• On the formation of planetary systems via oligarchic growth in thermally evolving viscous discs
• Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems
• Global MHD simulations of stratified and turbulent protoplanetary discs. I. Model properties
• Rapid Formation of Icy Super-Earths and the Cores of Gas Giant Planets
• Building Giant-Planet Cores at a Planet Trap
• Migration and Growth of Protoplanetary Embryos I: Convergence of Embryos in Protoplanetary Disks
• Resonances of Multiple Exoplanets and Implications for Their Formation

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