学术报告:行星胚胎在原行星盘中的迁移和成长

题目:行星胚胎在原行星盘中的迁移和成长
 
报告人:刘倍贝 博士 (北京大学天文系)
 
时间:6月17日(周三)下午3:30
 
地点:物理机电航空大楼438
 
摘要:
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. 
Here we build a model relied on the hypothesis that protoplanetary
embryos migrate extensively before they are 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 capable  to simulate the convergent migration of embryos, their close encounters
and coagulations. Our results indicate, around classical T Tauris stars, the
progenitor super-critical-mass cores of gas giant planets primarily
form in 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 disks with modest
mass accretion rates, due to the mean motion resonance barrier and retention efficiency.