Speaker : Prof. Young-Sun Lee (Chungnam National University)
TITLE : Carbon-Enhanced Metal-Poor (CEMP) Stars in the Milky Way
ABSTRACT : The objective-prism surveys such as HK and Hamburg ESO (HES) discovered numerous Very Metal-Poor (VMP; [Fe/H] < -2.0) stars in the Milky Way. Recently, the number of VMP stars has been dramatically increased to many tens of thousands, thanks to Sloan Digital Sky Survey (SDSS) and Sloan Extension for Galactic Understand and Exploration (SEGUE). Detailed chemical-abundance analyses, based on high-resolution spectroscopic follow-up, have revealed that, while most VMP stars exhibit similar abundance patterns, there are numerous examples of objects with peculiar chemical patterns. Among the chemically peculiar stars with [Fe/H] < -2.0, objects with enhanced carbon abundance are the most common variety. These are called Carbon-Enhanced Metal-Poor (CEMP) stars. One of the most interesting aspects of the CEMP stars is that the fraction of the CEMP stars increases as the metallicity decreases. In this talk, I will review the current understanding of the CEMP stars and discuss their implication to the first-generation stars and the origin of the Milky Way galaxy.