Chemical composition of extremely metal-poor stars in the Sextans dwarf spheroidal galaxy

Abstract

Context. Individual stars in dwarf spheroidal galaxies around the Milky Way Galaxy have been studied both photometrically and spectroscopically. Extremely metal-poor stars among them are very valuable because they should record the early enrichment in the Local Group. However, our understanding of these stars is very limited because detailed chemical abundance measurements are needed from high resolution spectroscopy. Alms. To constrain the formation and chemical evolution of dwarf galaxies, metallicity and chemical composition of extremely metal-poor stars are investigated. Methods. Chemical abundances of six extremely metal-poor ([Fe/H] < -2.5, as found in the Galactic halo. ©ESO 2009.