(Proposal ID) S16B-084 (PI) Matsuno, Tadafumi (Proposal Title) Young \alpha-Rich Stars: Are They Chemically Distinct Population? (Abstract) The abundance ratios between alpha elements and Fe ([alpha/Fe]) are expected to be higher in older stars (lower in younger stars) in standard chemical evolution models, reflecting the longer time-scale of type Ia supernovae that produce large amount of Fe than type II supernovae that mainly provide alpha elements. Recent stellar seismology with COROT and Kepler, along with spectroscopic studies with APOGEE/SDSS, however, reported the existence of a small group of young alpha-rich stars, which is not expected in standard chemical evolution models. We propose to obtain high resolution optical spectroscopy for 13 young alpha-rich stars identified by the recent studies to investigate this important class of objects. The primary purpose of this program is to confirm their existence by optical high resolution spectroscopy, which is well established by previous studies, for Fe-peak elements and alpha elements. The second purpose is to investigate abundance ratios of neutron- capture elements that provide useful constraints on the indication of this class of objects in the Galactic chemical evolution. These young alpha-rich stars have been reported very recently and urgent follow-up in this summer is desired. Hence, we request Keck/HIRES observation in August in which Subaru is not available.