Probing the Survival of Planetary Systems in Globular Clusters with Tidal Disruption Events
Probing the Survival of Planetary Systems in Globular Clusters with Tidal Disruption Events
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DOI：
10.3847/1538-4357/ab44d1
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
K. Kremer;D. D’Orazio;J. Samsing;S. Chatterjee;F. Rasio
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文献类型：
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作者：
K. Kremer;D. D’Orazio;J. Samsing;S. Chatterjee;F. Rasio
在不断增加的已确认系外行星列表中，在致密星团中发现的行星数量仍然很少。先前的分析表明，这可能部分归因于动态相互作用，这种相互作用可以将行星与其主恒星分开，限制星团中行星系统的生存。 Thus, alternative detection strategies may be necessary to study planets in clusters that may no longer be bound to a host.在这里，我们使用 N 体模型来探索致密星团中行星系统的演化。根据不同的初始条件，我们发现 10%–50% 的原始行星系统在星团的整个生命周期中通过动态遭遇而被打破，从而使星团中充满了“自由漂浮”的行星。此外，大量（30％–80％）的行星通过强烈的动力相遇和/或潮汐损失而从其宿主星团中弹出。此外，我们还发现行星会在其宿主星团的核心中自然地与恒星质量黑洞（BH）混合。结果，多达数百颗行星将因黑洞的近距离通道而受到潮汐扰动。我们表明，在银河系星系中，这些 BH 行星潮汐破坏事件 (TDE) 以高达 10−5 yr−1 的速率在星团中发生。原则上，这些 BH 行星 TDE 可能会被即将到来的瞬态巡天探测到，例如大型综合巡天望远镜，每年会发生几次事件，尽管识别这些事件可能具有挑战性。观测到的黑洞-行星潮汐表膨胀现象的发生率可能会对致密星团中行星系统和黑洞的形成和生存产生新的限制。
Among the growing list of confirmed exoplanets, the number of planets identified in dense star clusters remains sparse. Previous analyses have suggested that this may be due in part to dynamical interactions that can unbind planets from their host stars, limiting the survival of planetary systems in clusters. Thus, alternative detection strategies may be necessary to study planets in clusters that may no longer be bound to a host. Here, we use N-body models to explore the evolution of planetary systems in dense star clusters. Depending on various initial conditions, we show that 10%–50% of primordial planetary systems are broken through dynamical encounters over a cluster’s full lifetime, populating clusters with “free-floating” planets. Furthermore, a large number (30%–80%) of planets are ejected from their host cluster through strong dynamical encounters and/or tidal loss. Additionally, we show that planets naturally mix with stellar-mass black holes (BHs) in the cores of their host cluster. As a consequence, up to a few hundred planets will be tidally disrupted through close passages of BHs. We show that these BH–planet tidal disruption events (TDEs) occur in clusters at a rate of up to 10−5 yr−1 in a Milky-Way-type galaxy. In principle, these BH–planet TDEs may be detected by upcoming transient surveys such as the Large Synoptic Survey Telescope at a rate of a few events per year, although identification of these events may prove challenging. The observed rate of BH–planet TDEs could place new constraints upon the formation and survival of planetary systems and BHs in dense star clusters.