Ultra-short-period Planets Are Stable against Tidal Inspiral
Ultra-short-period Planets Are Stable against Tidal Inspiral
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DOI：
10.3847/1538-3881/aba74f
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发表时间：
2020-07
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影响因子：
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通讯作者：
J. Hamer;K. Schlaufman
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作者：
J. Hamer;K. Schlaufman
在单个系统和总体水平上都明确表明，热木星在其主星主序寿命结束之前经历了潮汐吸气。超短周期 (USP) 行星的轨道周期 P < 1 天，岩石成分，并且如果其宿主恒星内的潮汐耗散效率参数化独立于 P 和/或次生质量 Mp，预计将在与热木星相似的时间尺度上经历潮汐衰变。两类系统之间的任何差异都会表明具有常数的模型是不够的。如果USP行星经历潮汐涡旋，那么与没有USP行星的类似恒星相比，USP行星系统将相对年轻。因为它是相对年龄的代表，所以我们使用盖亚数据版本 2 的数据并辅以地面径向速度来计算 USP 行星候选宿主和非宿主恒星的银河速度弥散。我们发现主序USP行星候选宿主恒星的运动学与开普勒场中没有观测到USP行星的类似恒星一致。这表明 USP 行星宿主与场恒星具有相似的年龄，并且 USP 行星在其宿主恒星的主序寿命期间不会经历潮汐吸气。 USP 行星的生存要求 ≳ 107，P ≈ 0.7 天，并且 。该结果要求 取决于轨道周期和/或范围内的副星质量 和 。
It has been unambiguously shown both in individual systems and at the population level that hot Jupiters experience tidal inspiral before the end of their host stars’ main-sequence lifetimes. Ultra-short-period (USP) planets have orbital periods P < 1 day, rocky compositions, and are expected to experience tidal decay on similar timescales to hot Jupiters if the efficiency of tidal dissipation inside their host stars parameterized as is independent of P and/or secondary mass Mp. Any difference between the two classes of systems would reveal that a model with constant is insufficient. If USP planets experience tidal inspiral, then USP planet systems will be relatively young compared to similar stars without USP planets. Because it is a proxy for relative age, we calculate the Galactic velocity dispersions of USP planet candidate host and non-host stars using data from Gaia Data Release 2 supplemented with ground-based radial velocities. We find that main-sequence USP planet candidate host stars have kinematics consistent with similar stars in the Kepler field without observed USP planets. This indicates that USP planet hosts have similar ages to field stars and that USP planets do not experience tidal inspiral during the main-sequence lifetimes of their host stars. The survival of USP planets requires that ≳ 107 at P ≈ 0.7 day and . This result demands that depend on the orbital period and/or mass of the secondary in the range days and .