Architectures of Compact Super-Earth Systems Shaped by Instabilities
Architectures of Compact Super-Earth Systems Shaped by Instabilities
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DOI：
10.3847/1538-3881/ac5961
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
M. Goldberg;K. Batygin
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文献类型：
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作者：
M. Goldberg;K. Batygin
亚木星行星的致密非共振系统是行星形成过程中最常见的结果。尽管这些行星呈现出广泛的整体多样性，但它们在质量、半径和轨道间距上也表现出戏剧性的系统内一致性特征。尽管它们的形成和早期演化的细节鲜为人知，但由于行星-圆盘的相互作用，亚木星行星预计将以多谐振链的形式从其诞生的星云中出现。在这个场景的背景下，如果共振被星云后的动力学不稳定性破坏，那么观测到的系外行星系统的结构可以被广泛复制。在这里，我们生成一个特别的共振链样本，并使用一套N体模拟来表明不稳定性不仅可以重现观察到的周期比分布，而且所产生的碰撞也以与数据一致的方式修改了质量均匀性。此外，我们还证明了原始质量的均匀性，由共振链的样本加上动态雕刻所激发，自然地产生轨道周期间隔的一致性，类似于所观察到的。最后，我们发现，几乎所有的碰撞都会导致完美的合并，但可能需要某种形式的不稳定后衰减来完全解释今天亚木星系外行星的动态冷结构。
Compact nonresonant systems of sub-Jovian planets are the most common outcome of the planet formation process. Despite exhibiting broad overall diversity, these planets also display dramatic signatures of intrasystem uniformity in their masses, radii, and orbital spacings. Although the details of their formation and early evolution are poorly known, sub-Jovian planets are expected to emerge from their natal nebulae as multiresonant chains, owing to planet–disk interactions. Within the context of this scenario, the architectures of observed exoplanet systems can be broadly replicated if resonances are disrupted through postnebular dynamical instabilities. Here, we generate an ad hoc sample of resonant chains and use a suite of N-body simulations to show that instabilities can not only reproduce the observed period ratio distribution, but that the resulting collisions also modify the mass uniformity in a way that is consistent with the data. Furthermore, we demonstrate that primordial mass uniformity, motivated by the sample of resonant chains coupled with dynamical sculpting, naturally generates uniformity in orbital period spacing similar to what is observed. Finally, we find that almost all collisions lead to perfect mergers, but some form of postinstability damping is likely needed to fully account for the present-day dynamically cold architectures of sub-Jovian exoplanets.