ORBITAL MIGRATION OF LOW-MASS PLANETS IN EVOLUTIONARY RADIATIVE MODELS: AVOIDING CATASTROPHIC INFALL
ORBITAL MIGRATION OF LOW-MASS PLANETS IN EVOLUTIONARY RADIATIVE MODELS: AVOIDING CATASTROPHIC INFALL
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DOI：
10.1088/2041-8205/715/2/l68
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发表时间：
2010-03
期刊：
影响因子：
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通讯作者：
W. Lyra;S. Paardekooper;M. Mac Low
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文献类型：
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作者：
W. Lyra;S. Paardekooper;M. Mac Low
低质量行星的向外迁移最近在非正压性盘中被证明是可能的。我们在原行星盘的演化模型中检验这一结果的后果。行星向零力矩的平衡半径移动。由于粘性吸积和光蒸发，这些半径本身向内迁移。我们表明，随着表面密度和温度的下降，行星轨道迁移和磁盘耗尽的时间尺度最终变得相当，精确的时间取决于行星的质量。当这种情况发生时，行星与平衡半径解耦。然而，此时，气体表面密度已经太低，无法推动进一步的大规模迁移。一个质量更高的行星，10 M⊕，可以在盘的演化后期打开一个缺口，并停止迁移。在我们的模型中，1或0.1 M⊕的低质量行星在1 AU以上被释放，避免迁移到恒星中。我们的结果为最近的行星人口综合模型采用的降低迁移率提供了支持。
Outward migration of low-mass planets has recently been shown to be a possibility in non-barotropic disks. We examine the consequences of this result in evolutionary models of protoplanetary disks. Planet migration occurs toward equilibrium radii with zero torque. These radii themselves migrate inwards because of viscous accretion and photoevaporation. We show that as the surface density and temperature fall the planet orbital migration and disk depletion timescales eventually become comparable, with the precise timing depending on the mass of the planet. When this occurs, the planet decouples from the equilibrium radius. At this time, however, the gas surface density is already too low to drive substantial further migration. A higher mass planet, of 10 M⊕, can open a gap during the late evolution of the disk, and stops migrating. Low-mass planets, with 1 or 0.1 M⊕, released beyond 1 AU in our models avoid migrating into the star. Our results provide support for the reduced migration rates adopted in recent planet population synthesis models.