EVOLUTIONARY TRACKS OF TRAPPED, ACCRETING PROTOPLANETS: THE ORIGIN OF THE OBSERVED MASS–PERIOD RELATION
EVOLUTIONARY TRACKS OF TRAPPED, ACCRETING PROTOPLANETS: THE ORIGIN OF THE OBSERVED MASS–PERIOD RELATION
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被困、吸积原行星的演化轨迹：观测到的质量周期关系的起源
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Pudritz
中科院分区：
文献类型：
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作者：
Y. Hasegawa;R. Pudritz
大量观测到的系外行星（≳700）对它们的起源提供了重要的约束，正如从行星质量周期图推断的那样。图中最令人惊讶的特征是（1）气态巨行星在~500天（~1AU）的周期内（明显）堆积和（2）所谓的质量-周期关系，这表明行星质量是轨道周期的递增函数。我们在演化的原行星盘的行星陷阱中构建了生长行星的演化轨迹，并表明它们为这些观测特性如何产生提供了良好的物理理解。我们模型的基本特征是，原行星盘的不均匀性会产生多个（最多 3 个）捕获位点，以实现行星核心的快速（I 型）行星迁移。盘的粘性演化导致陷阱及其核心从大轨道周期到小轨道周期的缓慢径向运动。在我们的模型中，行星陷阱的缓慢向内运动与行星生长的标准核心吸积情景相结合。随着行星的生长，第二类迁移占据主导地位。行星的生长和径向运动最终因光蒸发造成的气盘扩散而停止。我们的模型做出了许多重要的预测：不同的行星子群反映了它们生长的行星陷阱的特性，导致了质量-周期关系，这些子群的存在自然地解释了~1天文单位的行星堆积，而来自冰线的演化轨迹确实使行星处于短周期，并填充了早期声称的“行星沙漠”——质量-半长轴图中的稀疏行星群。
The large number of observed exoplanets (≳700) provides important constraints on their origin as deduced from the mass–period diagram of planets. The most surprising features in the diagram are (1) the (apparent) pileup of gas giants at a period of ∼500 days (∼1 AU) and (2) the so-called mass–period relation, which indicates that planetary mass is an increasing function of orbital period. We construct the evolutionary tracks of growing planets at planet traps in evolving protoplanetary disks and show that they provide a good physical understanding of how these observational properties arise. The fundamental feature of our model is that inhomogeneities in protoplanetary disks give rise to multiple (up to 3) trapping sites for rapid (type I) planetary migration of planetary cores. The viscous evolution of disks results in the slow radial movement of the traps and their cores from large to small orbital periods. In our model, the slow inward motion of planet traps is coupled with the standard core accretion scenario for planetary growth. As planets grow, type II migration takes over. Planet growth and radial movement are ultimately stalled by the dispersal of gas disks via photoevaporation. Our model makes a number of important predictions: that distinct sub-populations of planets that reflect the properties of planet traps where they have grown result in the mass–period relation, that the presence of these sub-populations naturally explains a pileup of planets at ∼1 AU, and that evolutionary tracks from the ice line do put planets at short periods and fill an earlier claimed “planet desert”—a sparse population of planets in the mass–semimajor axis diagram.
DOI：
10.1088/2041-8205/715/2/l68
发表时间：
2010-03
期刊：
The Astrophysical Journal Letters
影响因子：
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作者：
W. Lyra;S. Paardekooper;M. Mac Low
通讯作者：
W. Lyra;S. Paardekooper;M. Mac Low