Abstract :
Recent observational studies of metal-deficient stars using large telescopes have revealed the elemental abundances for a wide range of atomic (mass) number for neutron-capture elements (31⩽Z⩽92), and also isotopic abundance ratios for several elements (e.g., Li, Mg, Eu). In this paper we review these recent studies, in particular the abundance pattern of light neutron-capture elements (Sr–Pd) and the Eu isotope ratios produced by the s-process.