Kinematics of mass-loss from the outer Lagrange point L2
Kinematics of mass-loss from the outer Lagrange point L2
复制标题
外部拉格朗日点 L2 的质量损失运动学
DOI：
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发表时间：
2019
影响因子：
4.8
通讯作者：
O. Pejcha
中科院分区：
文献类型：
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作者：
Dominika Hubova;O. Pejcha
我们研究了第二拉格朗日点 L2 附近的质量损失运动学，并将其应用于合并双星、共同包络演化以及相关的瞬态增亮。对于弹道粒子轨迹，我们描述了 L2 的初始速度和位置偏移，这些偏移导致无约束流出、回落，然后形成减速盘、与双星表面碰撞，或接近双星的流体动力冲击，其中一些粒子轨迹循环并自相交。后两个最终状态仅当轨迹以与 L2 的偏移或以不同于双星共转的速度矢量启动时发生。我们发现，来自二元、科里奥利力和初始条件的时间依赖性潮汐扭矩和急剧径向减小的潮汐扭矩之间的竞争导致 L2 附近结果的非平凡分布。具体来说，即使初始速度慢于共转，我们也发现一组初始位置偏移会导致无约束的流出。我们的结果将有助于解释流体动力学模拟中质量损失流的形态。
We investigate kinematics of mass-loss from the vicinity of the second Lagrange point L2 with applications to merging binary stars, common envelope evolution, and the associated transient brightenings. For ballistic particle trajectories, we characterize initial velocities and positional offsets from L2 that lead to unbound outflow, fall back followed by a formation of a decretion disc, collision with the binary surface, or a hydrodynamic shock close to the binary, where some particle trajectories loop and self-intersect. The latter two final states occur only when the trajectories are initiated with offset from L2 or with velocity vector different from corotation with the binary. We find that competition between the time-dependent and steeply radially decreasing tidal torques from the binary, Coriolis force, and initial conditions lead to a non-trivial distribution of outcomes in the vicinity of L2. Specifically, even for initial velocities slower than corotation, we find that a set of initial position offsets leads to unbound outflows. Our results will aid in the interpretation of the morphology of mass-loss streams in hydrodynamic simulations.