论文标题
从边界和未结合轨道上的恒星中的潮汐破坏耀斑
Tidal Disruption Flares from Stars on Marginally Bound and Unbound Orbits
论文作者
论文摘要
我们通过执行具有三个关键参数的三维平滑粒子流体动力学（SPH）模拟，研究了超大质量黑洞（SMBH）周围潮湿的恒星的质量质量后备率，该恒星具有三个关键参数：恒星由两种不同的指数（$ n = 1.5 = 1.5 $ n = 1.5 $和3美元）建模。恒星轨道特性的特征是五个轨道偏心率从$ e = 0.98 $到$ 1.02 $，五种不同的渗透因子从$β= 1 $到$ 3 $，其中$β$代表潮汐中断的比率到corecenter距离radii。我们得出了质量缩回率的分析公式，这是恒星密度曲线，轨道偏心率和穿透因子的函数的函数。此外，将潮汐破坏事件（TDE）分类为五种不同类型的两个关键偏心率：偏心（$ e <e _ {\ rm crit，1} $），边缘偏心（$ e _ {\ e _ {\ rm crit，1} （$ 1 <e <e _ {\ rm crit，2} $）和双曲线（$ e \ gtrsim {e _ {e _ {\ rm crit，2}} $）tdes tdes tdes tdes tdes被重新评估为$ e _ {\ rm crit，1} crit，2} = 1+2q^{ - 1/3}β^{k-1} $，其中$ q $是SMBH与恒星群众的比例，$ 0 <k \ k \ k \ sillsim2 $。我们发现质量后备率的渐近斜率随TDE类型而变化。抛物线TDE的渐近斜率接近$ -5/3 $，对于偏僻的TDE来说更陡峭，并且对于边缘双曲线的TDE来说是更厚的。偏僻的TDE的质量后备率远大于抛物线TDE病例，而偏僻的TDE的质量质量较小。略有未结合的TDE可能是休眠SMBH周围非常低的密度气盘的起源。
We study the mass fallback rate of tidally disrupted stars on marginally bound and unbound orbits around a supermassive black hole (SMBH) by performing three-dimensional smoothed particle hydrodynamic (SPH) simulations with three key parameters: the star is modeled by a polytrope with two different indexes ($n=1.5$ and $3$). The stellar orbital properties are characterized by five orbital eccentricities ranging from $e=0.98$ to $1.02$ and five different penetration factors ranging from $β=1$ to $3$, where $β$ represents the ratio of the tidal disruption to pericenter distance radii. We derive analytic formulae for the mass fallback rate as a function of the stellar density profile, orbital eccentricity, and penetration factor. Moreover, two critical eccentricities to classify tidal disruption events (TDEs) into five different types: eccentric ($e<e_{\rm crit,1}$), marginally eccentric ($e_{\rm crit,1}\lesssim{e}<1$), purely parabolic ($e=1$), marginally hyperbolic ($1<e<e_{\rm crit,2}$), and hyperbolic ($e\gtrsim{e_{\rm crit,2}}$) TDEs, are reevaluated as $e_{\rm crit,1}=1-2q^{-1/3}β^{k-1}$ and $e_{\rm crit,2}=1+2q^{-1/3}β^{k-1}$, where $q$ is the ratio of the SMBH to stellar masses and $0<k\lesssim2$. We find the asymptotic slope of the mass fallback rate varies with the TDE type. The asymptotic slope approaches $-5/3$ for parabolic TDEs, is steeper for marginally eccentric TDEs, and is flatter for marginally hyperbolic TDEs. The mass fallback rates of the marginally eccentric TDEs are much larger than the parabolic TDE case, while those of marginally hyperbolic TDEs are much smaller. Marginally unbound TDEs could be an origin of a very low density gas disk around a dormant SMBH.
