High-resolution spectroscopic analysis of a large sample of Li-rich giants found by LAMOST

The discovery of Li-rich giant has casted a new challenges for the standard stellar evolution models. To resolve this issue, the number of Li-rich giants has been updated by the development of worldwide surveys. Taking advantage of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), 44 newly discovered Li-rich giants are reported, which is the largest uniform high resolution sample until now. The high precision of atmospheric parameters and elemental abundances were derived by the spectral synthesis method based on the high-resolution and high signal-to-noise spectra. We perform a detailed analysis of the properties of these targets, including their evolutionary stages, infrared excess, projected rotational velocity (vsini) and the stellar population. We find that: (1) The associated phenomena of the Li-rich giants show that only three of them are rapid rotators and one have IR excess; (2) The Li-rich giants concentrate at the evolutionary status of the RGB bump, the red clump (RC) and the AGB. Our results imply that the origins of Li enrichment are most likely to be associated with the extra mixing in stellar interior, and the external scenario maybe make a minor contribution to the Li enhancement. Moreover, the different Li-rich episodes take place at the corresponding evolutionary stages. 

Speaker: 
Yutao Zhou (NAOC)
Location: 
first meeting room, KIAA
Time: 
Tue, 2019-03-19 12:00 to 13:00