标题： 潮汐相互作用的准共振理论 显示英文标题

标题： Quasi-Resonant Theory of Tidal Interactions

摘要： 当一个旋转系统经历与外部扰动体的瞬时引力相遇时，如果受害体的自转频率与扰动体的峰值轨道频率匹配，就会发生准共振。 这种相遇导致星系碰撞期间长尾和星桥的形成。 对于高速相遇，产生的速度扰动可以在冲量近似范围内描述。 然而，传统的冲量近似不区分顺行和逆行相遇，因此完全忽略了共振响应。 在这里，我们使用摄动理论，计算准共振现象对盘内恒星的影响。 推导了外部引力扰动体以直线或抛物线轨道经过时，由潮汐力引起的恒星速度和能量变化的显式表达式。 与数值限制三体计算的比较说明了我们分析的适用性。 显示英文摘要

摘要： When a spinning system experiences a transient gravitational encounter with an external perturber, a quasi-resonance occurs if the spin frequency of the victim matches the peak orbital frequency of the perturber. Such encounters are responsible for the formation of long tails and bridges of stars during galaxy collisions. For high-speed encounters, the resulting velocity perturbations can be described within the impulse approximation. The traditional impulse approximation, however, does not distinguish between prograde and retrograde encounters, and therefore completely misses the resonant response. Here, using perturbation theory, we compute the effects of quasi-resonant phenomena on stars orbiting within a disk. Explicit expressions are derived for the velocity and energy change to the stars induced by tidal forces from an external gravitational perturber passing either on a straight line or parabolic orbit. Comparisons with numerical restricted three-body calculations illustrate the applicability of our analysis.