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Chromospheric Activity of Periodic Variable Stars Based on the LAMOST Low- and Medium-resolution Spectral Survey
The Astrophysical Journal Supplement Series ( IF 8.7 ) Pub Date : 2021-04-07 , DOI: 10.3847/1538-4365/abe30b
Liu Long 1, 2 , Li-yun Zhang 2, 3 , Shao-Lan Bi 1 , Jianrong Shi 4 , Hong-Peng Lu 2 , Xianming L. Han 2, 5 , Haifeng Wang 6 , Misra Prabhakar 7
Affiliation  

We present a catalog of 75,867 periodic variable stars from data release 7 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. We calculated the chromospheric activity index, equivalent widths for 201,349 spectra, and excess fractional luminosity (${R}_{{\rm{H}}\alpha }^{{\prime} }$) for 130,796 spectra. Based on the intensity of the Hα line, we detected 30,719 F-, G-, and K-type variable stars with Hα fill-in or emission and 2521 M-type variable stars exhibiting Hα emission. Furthermore, 14,938 out of 30,573 periodic variable stars showed Hα variability. Analysis of samples with different spectral types confirmed that the activity fraction of stars with later spectral type clearly decreases as the absolute Galactic height increases away from the Galactic plane. The results also show that at the same absolute Galactic height, the activity fractions in eclipsing binaries are higher than those in single stars. In this study, we present the activity–rotation relations for F-, G-, K-, and M-type variable stars. The results of analysis show that rapid rotators keep a saturated value, and the absolute value of the power-law index exhibits an increasing trend from F- to K-type stars in the unsaturated regime. Moreover, we confirm that the angular momentum and magnetic momentum are positively correlated, which indicates that the αω dynamo may be working. In addition, we confirmed the correlations among the Hα, Hβ, Hγ, Hδ, Ca ii H&K, and Ca ii infrared triplet lines.



中文翻译:

基于LAMOST中低分辨率光谱巡天的周期变星色层活动

我们提供了来自大天区多目标光纤光谱望远镜数据发布 7 的 75,867 颗周期性变星的目录。我们计算了色球活动指数、201,349 个光谱的等效宽度和 130,796 个光谱的超额分数光度 ( ${R}_{{\rm{H}}\alpha }^{{\prime} }$)。基于H的强度α线,我们检测到30719 F-,G-,和K型变星用H α补平或发射和2521 M型变星表现出ħ α发射。此外,在 30,573 颗周期变星中,有 14,938 颗显示 H α变化性。对不同光谱类型样本的分析证实,随着远离银河平面的绝对银河高度增加,具有较晚光谱类型的恒星的活动率明显降低。结果还表明,在相同的绝对银河高度下,食双星的活动分数高于单星的活动分数。在这项研究中,我们展示了 F-、G-、K-和 M-型变星的活动-自转关系。分析结果表明,快速自转星保持饱和值,且幂律指数绝对值在非饱和状态下从F型星到K型星呈增大趋势。此外,我们确认角动量和磁动量呈正相关,这表明αω发电机可能正在工作。此外,我们还证实了 H α、H β、H γ、H δ、Ca ii H&K 和 Ca ii红外三重线之间的相关性。

更新日期:2021-04-07
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