CaII H&K emission distribution of ～120000 F,G and K stars in LAMOST DR1  

作　　者：Jing-Kun Zhao Terry D.Oswalt Yu-Qin Chen Jian-Rong Shi Ke-Feng Tan Xiang-Song Fang Gang Zhao Ming Yang Yong Zhang Yong-Hui Hou Yue-Fei Wang 

机构地区：[1]Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences [2]Embry-Riddle Aeronautical University,600 S.Clyde Morris Blvd.Daytona Beach FL 32114,USA [3]Nanjing Institute of Astronomical Optics & Technology,National Astronomical Observatories,Chinese Academy of Sciences

出　　处：《Research in Astronomy and Astrophysics》2015年第8期1282-1293,共12页天文和天体物理学研究（英文版）

基　　金：supported by the National Key Basic Research Program of China (973 program, 2014CB845701 and 2014CB845703);the National Natural Science Foundation of China (Grant Nos. U1431106, 11390371, 11233004, 11222326, 11150110135 and 11103034);Support from the US National Science Foundation (AST-1358787) to Embry-Riddle Aeronautical University

摘　　要：We present chromospheric activity index SHK measurements for 119 995 F, G and K stars with high signal-to-noise ratio（S/N 〉 80） spectra, extracted from LAMOST DR1 in SDSS g band. The index δS for each of these stars is calculated by the difference between its SHK value and the baseline determined from very inactive stars. The effect of metallicity on measurement of δS varies with stellar Teff. No evident Vaughan-Preston gap appears in our sample. The relation between δS and vertical distance from the Galactic plane is determined for stars with Teff 〈 5500 K. Stars with higher δS tend to be closer to the Galactic plane. Two open clusters in the DR1 sample, M45 and M67, exhibit the expected general trend that δS decays with age.For stars with Teff 〉 5500 K, similar δS levels appear in both young and old cluster stars, which supports Pace＇s suggestion that caution should be exercised when deriving the age of a single star by using its chromospheric activity. Finally, we investigate the relation between δS and the kinematics of our sample.We present chromospheric activity index SHK measurements for 119 995 F, G and K stars with high signal-to-noise ratio（S/N 〉 80） spectra, extracted from LAMOST DR1 in SDSS g band. The index δS for each of these stars is calculated by the difference between its SHK value and the baseline determined from very inactive stars. The effect of metallicity on measurement of δS varies with stellar Teff. No evident Vaughan-Preston gap appears in our sample. The relation between δS and vertical distance from the Galactic plane is determined for stars with Teff 〈 5500 K. Stars with higher δS tend to be closer to the Galactic plane. Two open clusters in the DR1 sample, M45 and M67, exhibit the expected general trend that δS decays with age.For stars with Teff 〉 5500 K, similar δS levels appear in both young and old cluster stars, which supports Pace＇s suggestion that caution should be exercised when deriving the age of a single star by using its chromospheric activity. Finally, we investigate the relation between δS and the kinematics of our sample.

关 键 词：stars： activity 

分 类 号：P148[天文地球—天体物理] P152[天文地球—天文学]