Planetary Formation Scenarios Revisited: Core-Accretion versus Disk Instability
Planetary Formation Scenarios Revisited: Core-Accretion versus Disk Instability
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DOI：
10.1086/517964
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
T. Matsuo;H. Shibai;T. Ootsubo;Motohide Tamura
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文献类型：
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作者：
T. Matsuo;H. Shibai;T. Ootsubo;Motohide Tamura
到目前为止，核心吸积和磁盘不稳定模型一直被用来解释行星的形成。这些模型有不同的条件，如行星质量、圆盘质量和形成气态巨星的金属丰度。核心吸积模型具有金属丰度条件（g型恒星为[Fe/H] > -1.17），形成的行星质量小于木星质量MJ的6倍。另一方面，盘不稳定模型不具备金属丰度条件，但要求盘的质量比最小质量太阳星云模型大15倍。形成的行星的质量超过2mj。这些结果与中心恒星的每种光谱类型的161颗探测到的行星进行了比较。结果表明，无论光谱类型如何，90%的探测到的行星都符合核心吸积模型。剩下的10%不在用核心吸积模型解释的区域，而是用磁盘不稳定模型解释的。我们导出了核心吸积模型中气态巨行星形成概率的金属丰度依赖性。将结果与观测到的气体巨星的比例进行比较，发现它们是一致的。另一方面，由于气态巨行星形成的条件与金属丰度无关，这一观测结果不能用盘不稳定性模型来解释。因此，迄今为止发现的大多数行星被认为是由核心吸积过程形成的，其余的则是由圆盘不稳定过程形成的。
The core-accretion and disk instability models have so far been used to explain planetary formation. These models have different conditions, such as planet mass, disk mass, and metallicity for formation of gas giants. The core-accretion model has a metallicity condition ([Fe/H] > -1.17 in the case of G-type stars), and the mass of planets formed is less than 6 times that of the Jupiter mass MJ. On the other hand, the disk instability model does not have the metallicity condition, but requires the disk to be 15 times more massive than the minimum mass solar nebulae model. The mass of planets formed is more than 2 MJ. These results are compared to the 161 detected planets for each spectral type of the central stars. The results show that 90% of the detected planets are consistent with the core-accretion model regardless of the spectral type. The remaining 10% are not in the region explained by the core-accretion model, but are explained by the disk instability model. We derived the metallicity dependence of the formation probability of gas giants for the core-accretion model. Comparing the result with the observed fraction having gas giants, they are found to be consistent. On the other hand, the observation cannot be explained by the disk instability model, because the condition for gas giant formation is independent of the metallicity. Consequently, most of planets detected so far are thought to have been formed by the core-accretion process, and the rest by the disk instability process.