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arXiv 2109.09775astro-ph.SR
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LAMOST中分辨率光谱测量中早型星的双星性

The Binarity of Early-type Stars from LAMOST Medium-resolution Spectroscopic Survey

Yanjun Guo, Jiao Li, Jianping Xiong, Jiangdan Li, Luqian Wang, Heran Xiong, Feng Luo, Yonghui Hou, Chao Liu, Zhanwen Han, Xuefei Chen

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摘要：

海量二进制文件在许多领域发挥着重要作用。识别大质量恒星，特别是大质量双星，是非常重要的。本文采用多条谱线等效宽度测量技术，对LAMOST中分辨率巡天的9,382颗早型星进行了识别，并将样本分为T1（$\sim$ O-B4）、T2（$\sim$ B5）、T3（$\sim$ B7）和T4（$\sim$ B8-A）四组。使用最大似然估计计算相对径向速度$RV_{\rm rel}$。具有明显的$RV_{\rm rel}$变化，并且至少大于15.57 km s $^{-1}$的恒星被鉴定为光谱双星。我们发现，所观察到的光谱二元馏分的四个组是$24.6\%\pm0.5\%$，$20.8\%\pm0.6\%$，$13.7\%\pm0.3\%$，和$7.4\%\pm0.3\%$，分别。假设轨道周期（$P$）和质量比（$q$）分别具有$f(P) \propto P^π$（1 \textless $P$ \textless 1000天）和$f(q) \propto q^κ$（0.1 \textless $q$ \textless 1）的内禀分布，我们进行了一系列Monte-Carlo模拟来校正用于估计内禀多重性的观测偏差。结果表明，四组化合物的内在二元分数分别为68 $\%\pm8\%$、52 $\%\pm3\%$、44 $\%\pm6\%$和44 $\%\pm6\%$。$π$的最佳估计值分别为-1 $\pm0.1$、-1.1 $\pm0.05$、-1.1 $\pm0.1$和-0.6 $\pm0.05$。T1和T2组的$κ$不能被约束，T3组的$\pm0.3$为-2.4，T4组的$\pm0.3$为-1.6。我们证实了一个减少的趋势，在二进制分数对晚型恒星的关系。目前还没有发现光谱类型与轨道周期分布之间的相关性，可能是由于观测节奏的限制。

英文摘要：

Massive binaries play significant roles in many fields. Identification of massive stars, particularly massive binaries, is of great importance. In this paper, by adopting the technique of measuring the equivalent widths of several spectral lines, we identified 9,382 early-type stars from LAMOST medium-resolution survey and divided the sample into four groups, T1 ($\sim$O-B4), T2 ($\sim$B5), T3 ($\sim$B7), and T4 ($\sim$B8-A). The relative radial velocities $RV_{\rm rel}$ were calculated using the Maximum Likelihood Estimation. The stars with significant changes of $RV_{\rm rel}$ and at least larger than 15.57km s$^{-1}$ were identified as spectroscopic binaries. We found that the observed spectroscopic binary fractions for the four groups are $24.6\%\pm0.5\%$, $20.8\%\pm0.6\%$, $13.7\%\pm0.3\%$, and $7.4\%\pm0.3\%$, respectively. Assuming that orbital period ($P$) and mass ratio ($q$) have intrinsic distributions as $f(P) \propto P^π$ (1\textless$P$\textless1000 days) and $f(q) \propto q^κ$ (0.1\textless$q$\textless1), respectively, we conducted a series of Monte-Carlo simulations to correct observational biases for estimating the intrinsic multiplicity properties. The results show that the intrinsic binary fractions for the four groups are 68$\%\pm8\%$, 52$\%\pm3\%$, 44$\%\pm6\%$, and 44$\%\pm6\%$, respectively. The best estimated values for $π$ are -1$\pm0.1$, -1.1$\pm0.05$, -1.1$\pm0.1$, and -0.6$\pm0.05$, respectively. The $κ$ cannot be constrained for groups T1 and T2 and is -2.4$\pm0.3$ for group T3 and -1.6$\pm0.3$ for group T4. We confirmed the relationship of a decreasing trend in binary fractions towards late-type stars. No correlation between the spectral type and the orbital period distribution has been found yet, possibly due to the limitation of observational cadence.

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