Oral Presentation

Searching for chemical relics in the Milky Way with LAMOST

Haining Li (NAOC), Gang Zhao (NAOC), etc.

Extremely Metal-Poor (EMP) stars ([Fe/H]<−3) are believed to form at the earliest stage of the Galactic chemical evolution. EMP stars are rare, but provide important record of the chemical yields of the first generations of stars and supernova, as well as on the formation of environments of the very beginning of the Galactic evolution. The huge database from LAMOST provides an unprecedented chance to enlarge the EMP star sample. We will introduce the project of EMP star survey with LAMOST, the ongoing progress, and the important results that have already been obtained. Based on DR1 and DR2 of LAMOST, a number of EMP stars have been newly discovered, including two Ultra Metal-Poor (UMP) stars with [Fe/H]<-4, of which only a dozen have been discovered in the past 30 years. Follow-up high-resolution observations with Magellan/MIKE and Subaru/HDS have been used to analyze the chemical abundances of these objects in details, improving our understanding of the earliest stage of the chemical environments of the Milky Way.