Stellar activity with LAMOST - II. Chromospheric activity in open clusters

doi:10.1093/mnras/sty212

CORC > 国家天文台 > 中国科学院国家天文台

	Stellar activity with LAMOST - II. Chromospheric activity in open clusters
	Fang, Xiang-Song 1; Zhao, Gang 1,2; Zhao, Jing-Kun 1; Kumar, Yerra Bharat 1
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2018-05-01
卷号	476 期号:1 页码:908-926
关键词	stars: activity stars: chromospheres stars: late-type stars: rotation
ISSN号	0035-8711
DOI	10.1093/mnras/sty212
英文摘要	We use the LAMOST spectra of member stars in Pleiades, M34, Praesepe, and Hyades to study how chromospheric activity varies as a function of mass and rotation at different age. We measured excess equivalent widths of H alpha, H beta, and Ca II K based on estimated chromospheric contributions from old and inactive field dwarfs, and excess luminosities are obtained by normalizing bolometric luminosity, for more than 700 late-type stars in these open clusters. Results indicate two activity sequences in cool spot coverage and Ha excess emission among GK dwarfs in Pleiades andMdwarfs in Praesepe and Hyades, paralleling with well-known rotation sequences. A weak dependence of chromospheric emission on rotation exists among ultrafast rotators in saturated regime with Rossby number Ro less than or similar to 0.1. In the unsaturated regime, chromospheric and coronal emission show similar dependence on Ro, but with a shift towards larger Ro, indicating chromospheric emission gets easily saturated than coronal emission, and/or convective turnover time-scales based on X-ray data do not work well with chromospheric emission. More interestingly, our analysis shows fully convective slow rotators obey the rotation-chromospheric activity relation similar to hotter stars, confirming the previous finding. We found correlations among H alpha, H beta, and Ca II K emissions, in which H alpha losses are more important than Ca II K for cooler and more active stars. In addition, a weak correlation is seen between chromospheric emission and photospheric activity that shows dependence on stellar spectral type and activity level, which provides some clues on how spot configuration varies as a function of mass and activity level.
资助项目	National Natural Science Foundation of China[11390371] ; National Natural Science Foundation of China[11233004] ; National Natural Science Foundation of China[11573035] ; National Natural Science Foundation of China[11625313] ; National Natural Science Foundation of China[11550110492] ; National Key Basic Research Program of China (973 program)[2014CB845701] ; Astronomical Big Data Joint Research Center ; Alibaba Cloud ; Chinese Academy of Sciences ; National Development and Reform Commission
WOS关键词	LOW-MASS STARS ; SOLAR-TYPE STARS ; MAIN-SEQUENCE STARS ; SUN-LIKE STARS ; DIGITAL SKY SURVEY ; X-RAY-EMISSION ; NGC 1039 M34 ; M-DWARFS ; COOL STARS ; ROTATIONAL VELOCITIES
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	OXFORD UNIV PRESS
WOS记录号	WOS:000429276700071
资助机构	National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 program) ; National Key Basic Research Program of China (973 program) ; Astronomical Big Data Joint Research Center ; Astronomical Big Data Joint Research Center ; Alibaba Cloud ; Alibaba Cloud ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Development and Reform Commission ; National Development and Reform Commission ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 program) ; National Key Basic Research Program of China (973 program) ; Astronomical Big Data Joint Research Center ; Astronomical Big Data Joint Research Center ; Alibaba Cloud ; Alibaba Cloud ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Development and Reform Commission ; National Development and Reform Commission ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 program) ; National Key Basic Research Program of China (973 program) ; Astronomical Big Data Joint Research Center ; Astronomical Big Data Joint Research Center ; Alibaba Cloud ; Alibaba Cloud ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Development and Reform Commission ; National Development and Reform Commission ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 program) ; National Key Basic Research Program of China (973 program) ; Astronomical Big Data Joint Research Center ; Astronomical Big Data Joint Research Center ; Alibaba Cloud ; Alibaba Cloud ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Development and Reform Commission ; National Development and Reform Commission
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/37118]
专题	中国科学院国家天文台
通讯作者	Fang, Xiang-Song
作者单位	1.Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China 2.Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Fang, Xiang-Song,Zhao, Gang,Zhao, Jing-Kun,et al. Stellar activity with LAMOST - II. Chromospheric activity in open clusters[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2018,476(1):908-926.
APA	Fang, Xiang-Song,Zhao, Gang,Zhao, Jing-Kun,&Kumar, Yerra Bharat.(2018).Stellar activity with LAMOST - II. Chromospheric activity in open clusters.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,476(1),908-926.
MLA	Fang, Xiang-Song,et al."Stellar activity with LAMOST - II. Chromospheric activity in open clusters".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 476.1(2018):908-926.