Classification of Tidal Disruption Events Based on Stellar Orbital Properties
Classification of Tidal Disruption Events Based on Stellar Orbital Properties
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DOI：
10.3847/1538-4357/aab0a5
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发表时间：
2018-02
期刊：
影响因子：
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通讯作者：
K. Hayasaki;Shiyan Zhong;Shuo Li;P. Berczik;R. Spurzem
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文献类型：
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作者：
K. Hayasaki;Shiyan Zhong;Shuo Li;P. Berczik;R. Spurzem
我们使用高精度的直接N体实验研究了中等质量到超大质量黑洞对束缚到非束缚轨道上的恒星的潮汐破坏率。接近黑洞的星星团中的恒星有三种轨道：偏心轨道、抛物线轨道和双曲线轨道。由于质量回落率表现出不同的变化取决于轨道类型，我们可以分为三个主要类别：偏心，抛物线和双曲线的潮汐破裂事件（TDE）。各自的TDE的特点是由两个临界值的轨道偏心率：下临界偏心率是一个低于偏心轨道上的恒星造成有限的，强烈的吸积，和上临界偏心率是一个以上的双曲线轨道上的恒星造成没有吸积。此外，我们发现，抛物型TDEs可以分为三个子类：精确抛物型，边际偏心，边际双曲。我们通过分析得出，边缘偏心的时间延迟方程的质量回退率可以更平坦，并且略高于与t−5/3成比例的标准回退率，而边缘双曲线的时间延迟方程的质量回退率可以更平坦，并且更低。我们确认使用N体实验，只有少数偏心，精确抛物，双曲型TDE可以发生在一个球形恒星系统与一个单一的中等质量超大质量黑洞。接近黑洞的恒星中，有相当一部分会引起轻微的偏心或轻微的双曲时间延迟效应。
We study the rates of tidal disruption of stars on bound to unbound orbits by intermediate-mass to supermassive black holes using high-accuracy direct N-body experiments. Stars from the star cluster approaching the black hole can have three types of orbit: eccentric, parabolic, and hyperbolic. Since the mass fallback rate shows different variabilities depending on the orbital type, we can classify tidal disruption events (TDEs) into three main categories: eccentric, parabolic, and hyperbolic. The respective TDEs are characterized by two critical values of the orbital eccentricity: the lower critical eccentricity is the one below which stars on eccentric orbits cause finite, intense accretion, and the upper critical eccentricity is the one above which stars on hyperbolic orbits cause no accretion. Moreover, we find that parabolic TDEs can be divided into three subclasses: precisely parabolic, marginally eccentric, and marginally hyperbolic. We analytically derive that the mass fallback rate of marginally eccentric TDEs can be flatter and slightly higher than the standard fallback rate proportional to t−5/3, whereas it can be flatter and lower for marginally hyperbolic TDEs. We confirm using N-body experiments that only a few eccentric, precisely parabolic, and hyperbolic TDEs can occur in a spherical stellar system with a single intermediate-mass to supermassive black hole. A substantial fraction of the stars approaching the black hole would cause marginally eccentric or marginally hyperbolic TDEs.