Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state
Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state
复制标题
高偏心双星中的动力潮汐：混沌、耗散和准稳态
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
D. Lai
中科院分区：
文献类型：
--
作者：
M. Vick;D. Lai
高度偏心的双星系统出现在许多天体物理环境中，从密集星团中的潮汐捕获，大质量黑洞破坏恒星的前兆，到巨型行星的高度偏心迁移。在高度偏心的双星中，一个物体的潮汐势能在中心附近通过时激发另一个物体的振荡模式，导致模式和双星轨道之间的能量交换。这些模式在多个通道上表现出三种行为之一：低振幅振荡，对应于轨道频率和模式频率之间的共振的大振幅振荡，以及混沌增长。我们用迭代映象研究了这些现象，充分探索了模演化是如何依赖于中心距等参数的。此外，我们还发现，模式能量的耗散导致准稳态，即使在模式振幅最初随机增长的系统中，轨道的逐渐衰减也会被共振打断。由于模式振幅和耗散的混沌增长，新捕获的黑洞周围的恒星可能会经历显著的轨道衰减和加热。一颗被推入高偏心轨道的巨行星可能会经历类似的效应，成为一颗热的或温暖的木星。
Highly eccentric binary systems appear in many astrophysical contexts, ranging from tidal capture in dense star clusters, precursors of stellar disruption by massive black holes, to high-eccentricity migration of giant planets. In a highly eccentric binary, the tidal potential of one body can excite oscillatory modes in the other during a pericenter passage, resulting in energy exchange between the modes and the binary orbit. These modes exhibit one of three behaviors over multiple passages: low-amplitude oscillations, large amplitude oscillations corresponding to a resonance between the orbital frequency and the mode frequency, and chaotic growth. We study these phenomena with an iterative map, fully exploring how the mode evolution depends on the pericenter distance and other parameters. In addition, we show that the dissipation of mode energy results in a quasi-steady state, with gradual orbital decay punctuated by resonances, even in systems where the mode amplitude would initially grow stochastically. A newly captured star around a black hole can experience significant orbital decay and heating due to the chaotic growth of the mode amplitude and dissipation. A giant planet pushed into a high-eccentricity orbit may experience a similar effect and become a hot or warm Jupiter.