The r- and s-process nuclei in the early history of the galaxy - HD 122563

Abstract

Atomic nuclei generated by s(low) and r(apid) fluxes of neutrons carry important information about the very late stages of stellar evolution in the Galaxy. The classic method of tracing the stellar nucleosynthesis sites of the early galactic generations is to compare the abundance pattern of extremely metal-poor stars to that of the sun. This approach fails almost completely for the heavier rare earths. The present study has the objective to supply reliable, more detailed abundances of the rare earth elements in metal-deficient stars. A detailed analysis is reported of the brightest extremely metal-deficient star in the sky, HD 122563. Light-element abundances, coupled with the high luminosity of HD 122563, clearly indicate a star in an advanced evolutionary state. New observational data of high-resolution and high signal-to-noise ratio in the blue and ultraviolet spectral regions of HD 122563 are presented. Attention is giveen to a model atmosphere analysis of HD 122563. Elemental abundances are presented and implications for galactic nucleosynthesis are discussed.