Crowding-out of giants by dwarfs : An origin for the lack of companion planets in hot Jupiter systems
Crowding-out of giants by dwarfs : An origin for the lack of companion planets in hot Jupiter systems
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矮星对巨星的挤出：热木星系统中缺乏伴星的起源
DOI：
10.1088/2041-8205/778/1/l9
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
小林 浩
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文献类型：
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作者：
荻原 正博;犬塚 修一郎;小林 浩
我们调查的形成接近类地行星的行星胚胎的影响下，热木星（HJ）使用引力N体模拟，包括气体盘和类地行星（例如，I型迁移）之间的引力相互作用。我们的模拟表明，几个类地行星有效地形成在HJ的轨道之外，形成一个行星链，并且它们都通过共振直接或间接地与HJ发生引力相互作用，这导致HJ向内迁移。我们把这种诱导迁移的机制称为”挤出“。“HJ最终因与中心星星的碰撞而消失，只剩下几颗类地行星。我们还发现，挤出效应的效率依赖于模型参数，例如，更重的磁盘，更有效的挤出是。当行星形成发生在一个巨大的磁盘，HJ可以失去中央星星，从来没有观察到。另一方面，对于质量较小的盘，HJ和类地行星可以共存;然而，伴星可能低于当前观测的检测极限。在这两种情况下，具有HJ和类地行星的系统几乎没有机会被发现。因此，我们的模型自然地解释了在HJ系统中缺乏伴行星，而不管盘质量如何。实际上，我们的模型为未来的观测提供了理论预测;在HJ之外可以发现更多的行星，它们的质量通常应该很小。
We investigate the formation of close-in terrestrial planets from planetary embryos under the influence of a hot Jupiter (HJ) using gravitational N-body simulations that include gravitational interactions between the gas disk and the terrestrial planet (eg, type I migration). Our simulations show that several terrestrial planets efficiently form outside the orbit of the HJ, making a chain of planets, and all of them gravitationally interact directly or indirectly with the HJ through resonance, which leads to inward migration of the HJ. We call this mechanism of induced migration of the HJ" crowding-out." The HJ is eventually lost through collision with the central star, and only several terrestrial planets remain. We also find that the efficiency of the crowding-out effect depends on the model parameters; for example, the heavier the disk is, the more efficient the crowding-out is. When planet formation occurs in a massive disk, the HJ can be lost to the central star and is never observed. On the other hand, for a less massive disk, the HJ and terrestrial planets can coexist; however, the companion planets may be below the detection limit of current observations. In both cases, systems with a HJ and terrestrial planets have little chance of detection. Therefore, our model naturally explains the lack of companion planets in HJ systems regardless of the disk mass. In effect, our model provides a theoretical prediction for future observations; additional planets can be discovered just outside the HJ, and their masses should generally be small.