Statistics of N-body simulations — IV. Unequal masses with a tidal field
Statistics of N-body simulations — IV. Unequal masses with a tidal field
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N体模拟的统计——潮汐场的不等质量
DOI：
10.1093/mnras/286.3.709
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发表时间：
1997
影响因子：
4.8
通讯作者：
D. Heggie
中科院分区：
文献类型：
--
作者：
M. Giersz;D. Heggie
我们报告了大量的碰撞N体模拟，包括质谱和潮汐场的结果。通过与本系列早期论文的比较，我们强调了进化与孤立系统中观察到的进化的不同之处。我们表明，演变几乎没有改变，如果潮汐场被替换为潮汐截止。核心崩溃几乎不受潮汐的影响，但随后的崩溃后膨胀最终被逆转的时间，潮汐限制变得重要。在孤立的模型中，质量分离几乎在核心坍缩结束时停止;核心反弹后，平均质量大幅增加，这是由低质量恒星的优先逃逸造成的。快速质量分离的早期阶段的特征也是在系统内部接近均分，尽管外部还远未达到均分。然而，即使在这里，在坍缩后的膨胀中也有一种缓慢的均分趋势，因为外部的潮汐剥离逐渐暴露出部分建立均分的星团部分。类似的评论适用于各向异性的演变。核心的演变是vIrtally不受潮汐影响，直到核心反弹后，在后期崩溃后的演变有一个趋势，核心的质量略有减少，而它几乎是恒定的孤立的模型。类似地，在潮汐的存在下，系统中双星的平均数量在核心坍缩结束后趋于减少。总的内部结合能在绑定二进制是小于在孤立系统的崩溃后的演变的可比阶段。在总的能量收支中，孤立模型和潮汐限制模型之间的一个明显区别是，逃逸的单个恒星的能量最初是负的，尽管随着三体相互作用的喷出物携带的能量变得占主导地位，它会变成正的。
We report results of a large number of collisional N-body simulations including a mass spectrum and a tidal field. We emphasize the ways in which evolution differs from that observed in isolated systems, by comparison with earlier papers in this series. We show that the evolution hardly alters if the tidal field is replaced by a tidal cut-off. Core collapse is almost unaffected by the tide, but the subsequent post collapse expansion is eventually reversed by the time that tidal limitation becomes important. As in isolated models, mass segregation almost stops by the end of core collapse; after core bounce there is a substantial increase in the mean mass, caused by preferential escape of stars of low mass. The early phase of rapid mass segregation is also characterized by an approach to equipartition in the inner parts of the system, although the outer parts remain far from equipartition. Even here, however, there is a slow tendency to equipartition in post-collapse expansion, as the tidal stripping of the outer parts gradually exposes parts of the cluster where equipartition was partially established. Similar remarks apply to the evolution of the anisotropy. The evolution of the core is vIrtually unaffected by the tide until well after core bounce; in late post-collapse evolution there is a tendency for the mass of the core to decrease slightly, whereas it is nearly constant in isolated models. Similarly, in the presence of a tide the mean number of binaries in the system tends to decrease after the end of core collapse. The total internal binding energy in bound binaries is smaller than at comparable stages of post-collapse evolution in isolated systems. In the overall energy budget, one obvious difference between isolated and tidally limited models is that the energy of escaping single stars is initially negative, although it becomes positive later as the energy carried off by ejecta from three body interactions becomes dominant.