학술논문
Evidence of Multiple r-Process Sites in the Early Galaxy: New Observations of CS 22892–052**Based on observations obtained with the Keck I Telescope of the W. M. Keck Observatory, which is operated by the California Association for Research in Astronomy (CARA, Inc.) on behalf of the University of California and the California Institute of Technology.
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article
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Source
The Astrophysical Journal. 533(2)
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Language
Abstract
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/=56) stable neutron-capture elements in CS 22892-052 match well the scaled solar system r-process abundance distribution. From the observed Th abundance, an average age of approximately 16+/-4 Gyr is derived for CS 22892-052, consistent with the lower age limit of approximately 11 Gyr derived from the upper limit on the U abundance. The concordance of scaled solar r-process and CS 22892-052 abundances breaks down for the lighter neutron-capture elements, supporting previous suggestions that different r-process production sites are responsible for lighter and heavier neutron-capture elements.