Chromospheric Activity of M Stars Based on LAMOST Low- and Medium-resolution Spectral Surveys

Author:

Zhang Li-yunORCID,Meng Gang,Long LiuORCID,Shi JianrongORCID,Zhong Ming,Han Xianming L.,Misra PrabhakarORCID,Wang HaifengORCID

Abstract

Abstract We have used the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) low-resolution and medium-resolution spectroscopic surveys to explore the chromospheric statistical properties and variations of M stars. There are 738,477 LAMOST low-resolution spectra of 622,523 M stars. We have calculated equivalent widths of the Ca ii H&K, Hα, Hβ, Hγ, Hδ, He i D3, and Ca ii infrared triplet lines. Based on the Hα EWs, we found that 33,374 objects showed Hα emissions. We revised the relationship between the active fraction and spectral subtype, and confirmed that the active fractions increased from M0 to M3, and possibly declined from M4 to subsequent types. Among 86,005 objects with repeated spectra, 19,422 objects showed Hα variations. The variation fraction of stars with M4 and subsequent types with a fully convective envelope was higher than those of M0–M3 with a partially convective envelope. By combining the distances from Gaia, we have determined the positions of the M dwarfs in the catalog for M stars. The active fraction decreased rapidly in the height range of 0–400 pc above and below the Galactic plane, and maintained a steady trend in 400–1000 pc. We cross-matched the M catalog of the LAMOST low-resolution survey with LAMOST medium-resolution spectra. We obtained 272,181 spectra of 13,355 M objects and calculated the Hα EWs. Among them, 3813 stars show variations, which might be caused by chromospheric activity evolution with orbital phase or time. The Hα emission for 972 objects shows variations over short and long timescales, especially on short timescales of 20 minutes.

Funder

Zhangliyun

Publisher

American Astronomical Society

Subject

Space and Planetary Science,Astronomy and Astrophysics

Cited by 15 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3