Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system
Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system
复制标题
先快后慢的迁移再现了 TRAPPIST-1 系统的质量分布
DOI：
10.1051/0004-6361/202142354
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发表时间：
2022
影响因子：
6.5
通讯作者：
Suzuki Takeru K.
中科院分区：
文献类型：
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作者：
Ogihara Masahiro;Kokubo Eiichiro;Nakano Ryuunosuke;Suzuki Takeru K.
TRAPPIST-1系统在各个方面都是一个标志性的行星系统（例如，可居住性、共振关系和多重性），因此引起了相当大的关注。TRAPPIST-1行星的质量分布有两个特点：两颗内行星很大，外轨道上的四颗行星的质量随着轨道距离的增加而增加。这些特征的起源不能用以前的形成模型来解释。AimsWe调查TRAPPIST-1系统的质量分布是否可以通过行星形成模型usingN-body simulation.MethodsWe使用的气体盘演化模型周围的低质量星星构建通过考虑磁盘风和遵循的增长和轨道迁移从行星胚胎与隔离质量，结果发现，从初始阶段开始，内轨道行星发生快速的轨道迁移，并且在内盘边缘附近的并合生长增强。这使得内行星变得更大。与此同时，与内行星相比，外轨道的行星迁移速度更慢，并且不经常与邻近行星相撞。因此，保持着向外轨道质量增加的趋势，称为反向质量排名。最终的质量分布大致同意的质量分布在TRAPPIST-1 system.ConclusionsWe发现，在TRAPPIST-1系统中的质量分布可以再现时，胚胎经历快速迁移，并成为被困在磁盘内边缘附近，然后更多的大规模胚胎进行较慢的迁移。这种迁移转变可以在具有盘风的盘演化模型中自然实现。
ContextThe TRAPPIST-1 system is an iconic planetary system in various aspects (e.g., habitability, resonant relation, and multiplicity) and hence has attracted considerable attention. The mass distribution of the TRAPPIST-1 planets is characterized by two features: the two inner planets are large, and the masses of the four planets in the outer orbit increase with orbital distance. The origin of these features cannot be explained by previous formation models.AimsWe investigate whether the mass distribution of the TRAPPIST-1 system can be reproduced by a planet formation model usingN-body simulations.MethodsWe used a gas disk evolution model around a low-mass star constructed by considering disk winds and followed the growth and orbital migration from planetary embryos with the isolation mass, which increases with orbital distance.ResultsAs a result, we find that from the initial phase, planets in inner orbits undergo rapid orbital migration, and the coalescence growth near the inner disk edge is enhanced. This allows the inner planets to grow larger. Meanwhile, compared with the inner planets, planets in outer orbits migrate more slowly and do not frequently collide with neighboring planets. Therefore, the trend of increasing mass toward the outer orbit, called reversed mass ranking, is maintained. The final mass distribution approximately agrees with the two features of the mass distribution in the TRAPPIST-1 system.ConclusionsWe discover that the mass distribution in the TRAPPIST-1 system can be reproduced when embryos experience rapid migration and become trapped near the disk inner edge, and then more massive embryos undergo slower migration. This migration transition can be achieved naturally in a disk evolution model with disk winds.