First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor (&sqbl0;Fe&solm0;H&sqbr0;=-3.1) halo field giant star CS 22892-052. Using new high-resolution, high signal-to-noise ratio spectra, abundances of more than 30 neutron-capture elements (Z>30) have been determined. Six elements in the 40<Z<56 domain (Nb, Ru, Rh, Pd, Ag, and Cd) have been detecte...

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy, responsible for neutron-capture synthesis and the progenitors of the halo stars, were rapidly evolving. Abundance comparisons among several halo stars show that the h...

We report on observations of six giants in the globular cluster M15 (NGC 7078) using the Subaru Telescope to measure neutron-capture elemental abundances. Our abundance analyses based on high-quality blue spectra confirm the star-to-star scatter in the abundances of heavy neutron-capture elements (e.g., Eu), and no significant s-process contribution to them, as was found in previous studies. We...

Presolar SiC grains formed around Asymptotic Giant Branch (AGB) stars during their carbon-rich phase and contain heavy elements in trace amounts showing the signature of the slow neutron capture process (s process). Thanks to recent advances in analysis techniques, SiC data now provide extremely precise information on neutron capture cross sections and AGB models. For example, high-precision da...