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arXiv 1407.7682astro-ph.EP
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开普勒-10行星系的形成

On the formation of the Kepler-10 planetary system

Caroline Terquem

摘要:

在本文中,我们调查了开普勒-10系统中的3和17个地球质量的固体行星通过碰撞和合并在初始种群的胚胎中形成所需的条件。通过进行大量的N体模拟,我们表明,初始人口的总质量必须显着大于两颗行星的质量,这两颗行星必须建立在比它们目前的位置更远的地方,距离中心恒星至少几个天文单位。这些行星必须成长得足够快,这样它们才能从剩余的、质量较小的核心中分离出来,迁移到现在的位置。当其他核心迁移进来时,磁盘的内边缘已经移出,因此这些核心今天无法被检测到。我们还计算了一个巨大的气体包层将被吸积超过的临界核心质量,并表明,它是大于17个地球质量,如果星子吸积到核心的速率大于10^{-6}地球质量每年。对于每年10^{-6}到10^{-5}个地球质量的星子吸积率,17个地球质量的核心预计不会吸积超过1个地球质量的气体。本文中的结果表明,像开普勒-10这样的行星系可能并不罕见,尽管它可能形成于一个相当大的圆盘中。

英文摘要:

In this paper, we investigate the conditions required for the 3 and 17 Earth mass solid planets in the Kepler-10 system to have formed through collisions and mergers within an initial population of embryos. By performing a large number of N-body simulations, we show that the total mass of the initial population had to be significantly larger than the masses of the two planets, and that the two planets must have built-up farther away than their present location, at a distance of at least a few au from the central star. The planets had to grow fast enough so that they would detach themselves from the population of remaining, less massive, cores and migrate in to their present location. By the time the other cores migrated in, the disc's inner edge would have moved out so that these cores cannot be detected today. We also compute the critical core mass beyond which a massive gaseous envelope would be accreted and show that it is larger than 17 Earth masses if the planetesimal accretion rate onto the core is larger than 10^{-6} Earth mass per year. For a planetesimal accretion rate between 10^{-6} and 10^{-5} Earth mass per year, the 17 Earth mass core would not be expected to have accreted more than about 1 Earth mass of gas. The results presented in this paper suggest that a planetary system like Kepler-10 may not be unusual, although it has probably formed in a rather massive disc.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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