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J. J. Cowan (U. Oklahoma), C. Sneden, I. Ivans (U. Texas), S. Burles (U. Chicago), T. C. Beers (Michigan State U.), G. Fuller (UCSD)
We are undertaking a comprehensive new abundance study of the ultra-metal-poor, neutron-capture-element-rich halo, field, giant star CS~22892-052. Combining data from new high resolution, high signal-to-noise echelle spectra from the Keck and McDonald telescopes, we have derived a new model atmosphere for this star and have determined the ``light'' element (Z \le 30) abundances to substantially better accuracy than was done in the McWilliam et al. (1995) survey. Employing this new model, we have analyzed (in much greater detail than Sneden et al. 1996) the abundances of about 30 neutron-capture (Z > 30) elements. Here we report abundances for three elements in the largely-unexplored atomic number domain 40 < Z < 56: Cd, Pd and Ag. These elements have been detected (for the very first time in an ultra-metal-poor star) in the near-UV spectral region of CS 22892-052. These new abundance determinations are compared with abundances of the heavier neutron-capture elements in this star and the scaled solar system r-process curve to provide new clues about the nature and the sites for the production of the neutron-capture elements in r-process nucleosynthesis.
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s follows:
www.nhn.ou.edu/~cowan/