论文标题
视觉二进制恒星的配对功能
Pairing function of visual binary stars
论文作者
论文摘要
基于华盛顿双星目录的1227个视觉二进制文件的全天空样本旨在通过专用人群合成模型来推断IMF，质量比和投影距离分布。 Gaia DR2和Hipparcos的视差用于验证距离分布。该模型在单星Tycho-2样品上进行了验证，并成功地重现了观察到的幅度和角度分离。投影的分离分布遵循$ f（s）\ sim s^{ - 1.2} $ in $ 10^2-2-2 \ cdot10^3 $ au范围1--4.5 $ m _ {\ odot} $主星。探索了几种算法作为配对函数。随机配对被自信地拒绝。考虑了主要受限（PCP）和拆分核对配对（SCP），即采用主要组件或总系统作为基本质量的方案。首选的IMF坡度为$α\ sim 2.8 $无论哪种方式。简单的幂律质量比分布不太可能，但是引入双胞胎过剩会带来有利的结果。具有$ f（q）\ sim q^{ - 1} $的PCP是首选具有微小双胞胎分数的PCP，当允许使用较大的双胞胎过量时，可以接受具有$ f（q）\ sim q^{ - 1.5} $的型号。当采用较大的电源定律时，SCP与PCP相似：$ f（q）\ sim q^{β+0.7} $。
An all-sky sample of 1227 visual binaries based on Washington Double Star catalogue is constructed to infer the IMF, mass ratio, and projected distance distribution with a dedicated population synthesis model. Parallaxes from Gaia DR2 and Hipparcos are used to verify the distance distribution. The model is validated on the single-star Tycho-2 sample and successfully reproduces the observed magnitudes and angular separations. The projected separation distribution follows $f(s)\sim s^{-1.2}$ in $10^2 - 2\cdot10^3$ AU range for 1--4.5 $m_{\odot}$ primary stars. Several algorithms are explored as pairing functions. Random pairing is confidently rejected. Primary-constrained (PCP) and split-core pairing (SCP), the scenarios adopting primary component's or total system's mass as fundamental, are considered. The preferred IMF slope is $α\sim 2.8$ either way. A simple power-law mass ratio distribution is unlikely, but the introduction of a twin excess provides a favourable result. PCP with $f(q) \sim q^{-1}$ is preferred with a tiny twin fraction, models with $f(q) \sim q^{-1.5}$ are acceptable when a larger twin excess is allowed. SCP is similar to PCP when a larger slope of the power law is adopted: $f(q)\sim q^{β+0.7}$.
