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Stellar activity with LAMOST - I. Spot configuration in Pleiades
Fang, Xiang-Song; Zhao, Gang; Zhao, Jing-Kun; Chen, Yu-Qin; Kumar, Yerra Bharat
2016-12-01
Source PublicationMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume463Issue:3Pages:2494-2512
AbstractWe use the spectra of Pleiades and field stars from the LAMOST DR2 archive to study how spottedness and activity vary as a function of mass at young ages. We obtained the standard TiOband strength by measuring TiO bands near 7050 angstrom from LAMOST spectra (R approximate to 1800) for a large sample of field GKM dwarfs with solar metallicity. Analysis shows that active dwarfs, including those of late G and early K types, have extra TiO absorption compared to their inactive counterparts, indicating the presence of cool spots on their surface. Active late K and M dwarfs show deeper TiO2 and shallower TiO4 compared to inactive stars at a given TiO5, which could be partly explained through cool spots. We estimated the cool-spot fractional coverage for 304 Pleiades candidates by modelling their TiO2 (and TiO5) band strength with respect to the standard value. The results show that the surfaces of a large fraction of K-and M-type members have very large spot coverage (similar to 50 per cent). We analysed the correlation between spot coverage, rotation and the amplitude of light variation, and found spot coverage on slow rotators (R-o > 0.1) increases with decreasing Rossby number R-o. Interestingly, we detected a saturation-like feature for spot coverage in fast rotators with a saturation level of 40-50 per cent. In addition, the spot distribution in hotter fast rotators is more symmetrical compared to slow rotators. More interestingly, we detected a large spot coverage in many M-type members with no or little light variation. In the bigger picture, these results provide important constraints for the stellar dynamos of these cool active stars.
SubtypeArticle
KeywordStars: Activity Stars: Late-type Stars: Rotation Starspots
WOS HeadingsScience & Technology ; Physical Sciences
Funding OrganizationNational Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Natural Science Foundation of China(U1431106) ; National Natural Science Foundation of China(U1431106) ; Chinese Academy of Sciences(2013FFJB0008) ; Chinese Academy of Sciences(2013FFJB0008) ; National Development and Reform Commission ; National Development and Reform Commission ; 2014CB845703) ; 2014CB845703) ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Natural Science Foundation of China(U1431106) ; National Natural Science Foundation of China(U1431106) ; Chinese Academy of Sciences(2013FFJB0008) ; Chinese Academy of Sciences(2013FFJB0008) ; National Development and Reform Commission ; National Development and Reform Commission ; 2014CB845703) ; 2014CB845703)
DOI10.1093/mnras/stw1923
WOS KeywordLOW-MASS STARS ; DIGITAL SKY SURVEY ; MAIN-SEQUENCE STARS ; CLUSTER NGC 2516 ; M-DWARFS ; ROTATIONAL VELOCITIES ; SPECTROSCOPIC SURVEY ; MAGNETIC ACTIVITY ; DATA RELEASE ; II-PEGASI
Indexed BySCI
Language英语
Funding OrganizationNational Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Natural Science Foundation of China(U1431106) ; National Natural Science Foundation of China(U1431106) ; Chinese Academy of Sciences(2013FFJB0008) ; Chinese Academy of Sciences(2013FFJB0008) ; National Development and Reform Commission ; National Development and Reform Commission ; 2014CB845703) ; 2014CB845703) ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Key Basic Research Programme of China (973 programme)(2014CB845701 ; National Natural Science Foundation of China(U1431106) ; National Natural Science Foundation of China(U1431106) ; Chinese Academy of Sciences(2013FFJB0008) ; Chinese Academy of Sciences(2013FFJB0008) ; National Development and Reform Commission ; National Development and Reform Commission ; 2014CB845703) ; 2014CB845703)
WOS Research AreaAstronomy & Astrophysics
WOS SubjectAstronomy & Astrophysics
WOS IDWOS:000393566000018
Citation statistics
Cited Times:10[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/8300
Collection光学天文研究部
AffiliationChinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China
Recommended Citation
GB/T 7714
Fang, Xiang-Song,Zhao, Gang,Zhao, Jing-Kun,et al. Stellar activity with LAMOST - I. Spot configuration in Pleiades[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2016,463(3):2494-2512.
APA Fang, Xiang-Song,Zhao, Gang,Zhao, Jing-Kun,Chen, Yu-Qin,&Kumar, Yerra Bharat.(2016).Stellar activity with LAMOST - I. Spot configuration in Pleiades.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,463(3),2494-2512.
MLA Fang, Xiang-Song,et al."Stellar activity with LAMOST - I. Spot configuration in Pleiades".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 463.3(2016):2494-2512.
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