Stellar activity with LAMOST - I. Spot configuration in Pleiades
文献类型：期刊论文
| 作者 | Fang, Xiang-Song ; Zhao, Gang; Zhao, Jing-Kun; Chen, Yu-Qin; Kumar, Yerra Bharat
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| 刊名 | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
 |
| 出版日期 | 2016-12-01 |
| 卷号 | 463期号:3页码:2494-2512 |
| 关键词 | stars: activity stars: late-type stars: rotation starspots |
| 英文摘要 | We 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. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | LOW-MASS STARS ; DIGITAL SKY SURVEY ; MAIN-SEQUENCE STARS ; CLUSTER NGC 2516 ; M-DWARFS ; ROTATIONAL VELOCITIES ; SPECTROSCOPIC SURVEY ; MAGNETIC ACTIVITY ; DATA RELEASE ; II-PEGASI |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000393566000018 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/8300]  |
| 专题 | 国家天文台_光学天文研究部 |
| 作者单位 | Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, 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 - 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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来源：国家天文台
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