PLANETARY CORE FORMATION WITH COLLISIONAL FRAGMENTATION AND ATMOSPHERE TO FORM GAS GIANT PLANETS
PLANETARY CORE FORMATION WITH COLLISIONAL FRAGMENTATION AND ATMOSPHERE TO FORM GAS GIANT PLANETS
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DOI：
10.1088/0004-637x/738/1/35
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发表时间：
2011-06
期刊：
影响因子：
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通讯作者：
H. Kobayashi;Hidekazu Tanaka;A. Krivov
中科院分区：
文献类型：
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作者：
H. Kobayashi;Hidekazu Tanaka;A. Krivov
大质量的行星核心（10倍地球质量）引发快速的气体吸积，形成气体巨行星，如木星和土星。我们调查的核心增长和核心的可能性，以达到这样一个关键的核心质量。在后期阶段，行星核心通过与小行星的碰撞而成长。微行星与行星核心的引力相互作用导致微行星的碰撞碎裂，减少了周围微行星的数量，从而减少了最终的核心质量。从小的微行星开始，碎片迅速移动，形成质量较小的核心。然而，行星核心在快速气体吸积之前获得了扩大其碰撞截面的大气。一旦行星核心超过火星质量，大气层就会显著加速核心的生长。我们表明，考虑到碎片和大气的影响，最初大的星子使足够大的核心形成。另一方面，由于大型星子的核心生长缓慢，因此需要一个巨大的磁盘才能使核心在磁盘寿命内充分增长。如果初始微行星直径为100公里的盘状星云的质量是最小质量太阳星云的10倍，那么在类木行星区域（>5 Au），行星核的质量可以超过10个地球质量。
Massive planetary cores (∼10 Earth masses) trigger rapid gas accretion to form gas giant planets such as Jupiter and Saturn. We investigate the core growth and the possibilities for cores to reach such a critical core mass. At the late stage, planetary cores grow through collisions with small planetesimals. Collisional fragmentation of planetesimals, which is induced by gravitational interaction with planetary cores, reduces the amount of planetesimals surrounding them, and thus the final core masses. Starting from small planetesimals that the fragmentation rapidly removes, less massive cores are formed. However, planetary cores acquire atmospheres that enlarge their collisional cross section before rapid gas accretion. Once planetary cores exceed about Mars mass, atmospheres significantly accelerate the growth of cores. We show that, taking into account the effects of fragmentation and atmosphere, initially large planetesimals enable formation of sufficiently massive cores. On the other hand, because the growth of cores is slow for large planetesimals, a massive disk is necessary for cores to grow enough within a disk lifetime. If the disk with 100 km sized initial planetesimals is 10 times as massive as the minimum mass solar nebula, planetary cores can exceed 10 Earth masses in the Jovian planet region (>5 AU).