论文标题
层次三重系统的动态破坏时间尺度和混乱行为
Dynamical disruption timescales and chaotic behavior of hierarchical triple systems
论文作者
论文摘要
我们使用直接$ n $ body模拟检查了层次三重系统的稳定性，而无需采用世俗的扰动近似。除了仅稳定/不稳定的标准外，我们还估计了它们的破坏时间尺度，特别注意内部轨道和外轨道之间的相互倾斜度。首先，我们通过\ citet {mardling1999，mardling2001}提高了对动力稳定性标准的拟合度，在先前的文献中广泛采用。特别是，我们发现稳定边界对相互倾斜度非常敏感。共面逆行三元组和正交的三元组比共兰纳尔前列三元组分别更稳定和不稳定。接下来，我们估计满足稳定性条件的三倍的破坏时间尺度，最高$ 10^9 $ $倍。时间尺度遵循\ citet {mushkin2020}预测的缩放，尤其是在高$ e_ \ mathrm {out} $的情况下，其随机步行模型最有效。我们获得了对破坏时间尺度的经验拟合度的改进，这表明共面逆行三元组明显比以前的预测更稳定。我们此外，发现对互惠倾斜的依赖性可以通过基于抛物线寄生虫遭遇近似的能量转移模型来解释。我们还表明，三元组的破坏时间尺度对初始参数的微小变化高度敏感，这反映了这些系统动力学的真正混乱性质。
We examine the stability of hierarchical triple systems using direct $N$-body simulations without adopting a secular perturbation approximation. We estimate their disruption timescales in addition to the mere stable/unstable criterion, with particular attention to the mutual inclination between the inner and outer orbits. First, we improve the fit to the dynamical stability criterion by \citet{Mardling1999,Mardling2001} widely adopted in the previous literature. Especially, we find that that the stability boundary is very sensitive to the mutual inclination; coplanar retrograde triples and orthogonal triples are much more stable and unstable, respectively, than coplanar prograde triples. Next, we estimate the disruption timescales of triples satisfying the stability condition up to $10^9$ times the inner orbital period. The timescales follow the scaling predicted by \citet{Mushkin2020}, especially at high $e_\mathrm{out}$ where their random walk model is most valid. We obtain an improved empirical fit to the disruption timescales, which indicates that the coplanar retrograde triples are significantly more stable than the previous prediction. We furthermore find that the dependence on the mutual inclination can be explained by the energy transfer model based on a parabolic encounter approximation. We also show that the disruption timescales of triples are highly sensitive to the tiny change of the initial parameters, reflecting the genuine chaotic nature of the dynamics of those systems.
