Abundances of neutron capture elements in population II stars

The paper presents new abundance results for 20 very metal poor Population II stars. High-resolution low-noise spectra in selected wavelength regions were obtained for each program star, and the spectra were examined using complete model atmosphere, line analysis, and spectrum synthesis techniques. The abundances of heavy elements formed predominantly by neutron capture processes are taken into account. It is shown that real star-to-star differences exist in the ratios of neutron capture element to iron-peak element abundances. Below stellar metallicities Fe/H of less than -2, all of the heavy-element abundance patterns indicate the presence of r-process synthesis events. 41 references.