arXiv 2209.092722022-09astro-ph.SRastro-ph.GA

LAMOST DR8早型星的统计性质

The statistical properties of early-type stars from LAMOST DR8

Yanjun Guo, Chao Liu, Luqian Wang, Jinliang Wang, Bo Zhang, Kaifan Ji, ZhanWen Han, XueFei Chen

发表信息：: A&A 667, A44 (2022)
DOI：: 10.1051/0004-6361/202244300

摘要：

大质量双星在许多天体物理学领域起着至关重要的作用。研究大质量双星的统计性质对于追踪大质量恒星的形成和限制恒星种群的演化至关重要。然而，对于大质量双星的统计特性还没有达成共识，主要是因为缺乏大量均匀的光谱观测样本。研究了早型星的内禀双星分数$f_{\rm b}^{\rm in}$、质量比$f(q)$和轨道周期$f(P)$的分布（包括O型、B型和A型星），并研究它们对有效温度$T_{\rm eff}$、恒星金属丰度[M/H]和投射速度$v\sin{i}$的依赖性，基于来自大天区多目标光纤光谱望远镜（LAMOST）数据发布8（DR 8）的均匀光谱样本。我们发现，$f_{\rm b}^{\rm in}$随着$T_\mathrm{eff}$的增加而增加。二元分数与样品中光谱的金属丰度呈正相关。在我们考虑的所有$v\sin{i}$值中，$f_{\rm b}^{\rm in}$具有恒定值$\sim$ 50\%。看来双星的星族在很大范围的$v\sin{i}$值上相对均匀地分布，而整个样本显示，大多数恒星都集中在低的$v\sin{i}$值（可能来自单个大质量恒星的强风和磁制动）和高的$v\sin{i}$值（可能来自双星的合并）。在$π$（$γ$）和$T_{\rm eff}$之间以及$π$（$γ$）和[M/H]之间没有发现相关关系。分布的不确定性随着观察节奏的增加而减小。

英文摘要：

Massive binary stars play a crucial role in many astrophysical fields. Investigating the statistical properties of massive binary stars is essential to trace the formation of massive stars and constrain the evolution of stellar populations. However, no consensus has been achieved on the statistical properties of massive binary stars, mainly due to the lack of a large and homogeneous sample of spectroscopic observations. We study the intrinsic binary fraction $f_{\rm b}^{\rm in}$ and distributions of mass ratio $f(q)$ and orbital period $f(P)$ of early-type stars (comprised of O-, B-, and A-type stars) and investigate their dependences on effective temperature $T_{\rm eff}$, stellar metallicity [M/H], and the projection velocity $v\sin{i}$, based on the homogeneous spectroscopic sample from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data Release Eight (DR8). We found that $f_{\rm b}^{\rm in}$ increases with increasing $T_\mathrm{eff}$. The binary fraction is positively correlated with metallicity for spectra in the sample. Over all the $v\sin{i}$ values we considered, the $f_{\rm b}^{\rm in}$ have constant values of $\sim$50\%. It seems that the binary population is relatively evenly distributed over a wide range of $v\sin{i}$ values, while the whole sample shows that most of the stars are concentrated at low values of $v\sin{i}$ (probably from strong wind and magnetic braking of single massive stars) and at high values of $v\sin{i}$ (likely from the merging of binary stars). Stellar evolution and binary interaction may be partly responsible for this.There are no correlations found between $π$($γ$) and $T_{\rm eff}$, nor for $π$($γ$) and [M/H]. The uncertainties of the distribution decrease toward a larger sample size with higher observational cadence.

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