Lithium Abundance of 17 Young Nearby Stars: High Resolution Spectrograph Observation with Lijiang 1.8 m Telescope
XING Li-feng1,2, CHANG Liang1,2
1. Yunnan Astronomical Observatory，Chinese Academy of Sciences，Kunming 650011, China
2. Key Laboratory for the Structure and Evolution of Celestial Objects，Chinese Academy of Sciences，Kunming 650011, China
Abstract：A high resolution echelle spectra for a sample of 18 stars，mainly composed of young solar type stars, is presented in this paper. Observations of these stars have been carried out with the 1.8 m Optical Telescope located at the Lijiang station of the Yunnan Astronomical Observatories, Chinese Academy of Science (YAOC). The high-resolution and high signal-to-noise ratio spectra of the observations suggest that the reformation of the Coude Echelle Spectrograph attached to the 2.16 m telescope at the Xinglong station of the National Astronomical Observatories, Chinese Academy of Science (NAOC) was successful. Based on these observations, the LiⅠ λ 670.8 nm equivalent widths and the lithium abundances of 17 nearby young stars were derived The empirical relationship for estimating the surface flux in the band pass k3925 to k3975 was applied to compute the CaⅡ emission flux. Using the lithium abundances and the CaⅡ emission flux, the relationship between the Li abundances and the CaⅡ emission flux was investigated . A clear correlation between the lithium abundances and the CaⅡ emission flux is found: as the CaⅡ emission flux became stronger, the lithium abundance decreases in our sample stars. Taking into account of the main features of the rotational evolution of low-mass stars: on the Pre-Main-Sequence, low-mass stars appear to spin up rapidly, and reach very rapid rotation rates at the Zero-Age-Main-Sequence(ZAMS); after ZAMS, the rotation period of star increase with increasing age (spin down). Our results support the chromospherically active solar-type star has high lithium abundances and the rotation-activity relation of young stars.
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