论文标题

对冲动加热的完全一般的非扰动治疗

A Fully General, Non-Perturbative Treatment of Impulsive Heating

论文作者

Banik, Uddipan, Bosch, Frank C. van den

论文摘要

通常使用遥远的潮汐近似(DTA)对待天体物理对象之间的冲动性接触,该近似近似值(DTA)假定影响参数($ b $)明显大于该受试者的特征性半径,$ r _ {\ mathrm {s}}} $,以及perturber,perturber,$ r _}然后将Perturber电势扩展为多极序列,并在四极术中截断。当Perturber比主题更扩展时,可以将此标准方法扩展到$ r _ {\ Mathrm {s}}} \ ll B <r _ {\ Mathrm {p}} $的情况。但是,对于与$ b $的订单$ r _ {\ mathrm {s}} $或较小的相遇,DTA通常过度预测冲动,$δ\ mathbf {v} $,因此,主题的内部能量变化,$δe_ {\ mathrm {\ mathrm {int} $ {\ mathrm {int} $。这是不幸的,因为这些近距离相遇是最有趣的,有可能导致潮汐捕获,大规模剥离或潮汐破坏。 DTA的另一个缺点是$Δe_{\ mathrm {int}} $与惯性时刻成比例,除非受试者被截断或具有比$ r^{ - 5} $快的密度曲线,否则它会发出差异。为了克服这些缺点,本文提出了对冲动性相遇的完全一般的,非扰动的治疗方法,这对于任何影响参数有效,并且不会因发散问题而受到阻碍,从而否定了截断对象的必要性。我们提供了$δ\ Mathbf {V} $的分析表达式,用于各种垂直概况,将我们的形式主义应用于直线遇到和偏心轨道上,并讨论由于相等质量星系之间的重力遭遇的潮汐冲击而引起的质量损失。

Impulsive encounters between astrophysical objects are usually treated using the distant tide approximation (DTA) for which the impact parameter, $b$, is assumed to be significantly larger than the characteristic radii of the subject, $r_{\mathrm{S}}$, and the perturber, $r_{\mathrm{P}}$. The perturber potential is then expanded as a multipole series and truncated at the quadrupole term. When the perturber is more extended than the subject, this standard approach can be extended to the case where $r_{\mathrm{S}} \ll b < r_{\mathrm{P}}$. However, for encounters with $b$ of order $r_{\mathrm{S}}$ or smaller, the DTA typically overpredicts the impulse, $Δ\mathbf{v}$, and hence the internal energy change of the subject, $ΔE_{\mathrm{int}}$. This is unfortunate, as these close encounters are the most interesting, potentially leading to tidal capture, mass stripping, or tidal disruption. Another drawback of the DTA is that $ΔE_{\mathrm{int}}$ is proportional to the moment of inertia, which diverges unless the subject is truncated or has a density profile that falls off faster than $r^{-5}$. To overcome these shortcomings, this paper presents a fully general, non-perturbative treatment of impulsive encounters which is valid for any impact parameter, and not hampered by divergence issues, thereby negating the necessity to truncate the subject. We present analytical expressions for $Δ\mathbf{v}$ for a variety of perturber profiles, apply our formalism to both straight-path encounters and eccentric orbits, and discuss the mass loss due to tidal shocks in gravitational encounters between equal mass galaxies.

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