Searching for extremely alpha-poor stars in the Galactic Halo

Abstract

AbstractA few alpha-poor stars that show severe departures (over 0.4 dex deficiency in alpha-element abundance) from the general enhanced alpha-element chemical abundance trends of the halo have been discovered in recent years, such as BD +80°245, G4-36 and CS 22966-043. These ratios suggest a different chemical enrichment history for these stars than for the majority of the halo. Similarly low-alpha abundance patterns are also seen in the Sagittarius dSph galaxy. We present a method for searching of extremely alpha-poor stars from low-resolution stellar spectra of LAMOST pilot survey and attempt to create a large sample of these particular Galactic halo stars.