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FROM BINARIES TO MULTIPLES. II. HIERARCHICAL MULTIPLICITY OF F AND G DWARFS

机译:从二进制到乘法。二。 F和G DWARF的分层多重性

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Statistics of hierarchical multiplicity among solar-type dwarfs are studied using the distance-limited sample of 4847 targets presented in the accompanying Paper?I. Known facts about binaries (multiplicity fraction 0.46, lognormal period distribution with median period 100?yr and logarithmic dispersion 2.4, and nearly uniform mass-ratio distribution independent of the period) are confirmed with a high statistical significance. The fraction of hierarchies with three or more components is 0.13 ± 0.01, and the fractions of targets with n = 1, 2, 3, ... components are 54:33:8:4:1. Subsystems in the secondary components are almost as frequent as in the primary components, but in half of such cases both inner pairs are present. The high frequency of those 2+2 hierarchies (4%) suggests that both inner pairs were formed by a common process. The statistics of hierarchies can be reproduced by simulations, assuming that the field is a mixture coming from binary-rich and binary-poor environments. Periods of the outer and inner binaries are selected recursively from the same lognormal distribution, subject to the stability constraint and accounting for the correlation between inner subsystems. The simulator can be used to evaluate the frequency of multiple systems with specified parameters. However, it does not reproduce the observed excess of inner periods shorter than 10?days, caused by tidal evolution.
机译:使用随附的论文?I中提出的4847个目标的距离受限样本,研究了太阳型矮人之间的等级多重性统计。已知关于二元数的事实(多重分数为0.46,中位数为100μyr的对数正态周期分布,对数离散为2.4,以及与周期无关的近乎均匀的质量比分布)具有很高的统计意义。具有三个或更多组成部分的层次结构分数为0.13±0.01,具有n = 1、2、3,...组成部分的目标分数为54:33:8:4:1。次要组件中的子系统几乎与主要组件中的子系统一样频繁,但是在这种情况的一半中,两个内部对都存在。这些2 + 2层次结构的较高频率(4%)表明两个内部对都是通过共同的过程形成的。假设该字段是来自富含二进制信息的环境和缺乏二进制信息的环境的混合,则可以通过模拟来复制层次结构的统计信息。外部和内部二进制的周期是从相同的对数正态分布中递归选择的,但要遵循稳定性约束并考虑内部子系统之间的相关性。模拟器可用于评估具有指定参数的多个系统的频率。但是,它并没有重现观察到的由潮汐演化引起的少于10天的内部周期过剩。

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