10:45 AM–12:33 PM, Monday, April 14, 2008
Hyatt Regency St. Louis Riverfront (formerly Adam's Mark Hotel), - St. Louis E
Sponsoring Unit:
DNP
Chair: Hendrik Schatz, Michigan State University
10:45 AM–11:21 AM
Anna Frebel
(McDonald Observatory, University of Texas at Austin)
In their atmospheres, old metal-poor Galactic stars retain
detailed information about the chemical composition of the
interstellar medium at the time of their birth. Extracting such
stellar abundances enables us to reconstruct the beginning of the
chemical evolution shortly after the Big Bang. About 5\% of
metal-poor stars with $\mbox{[Fe/H]}<-2.5$ display in their
spectrum a
strong enhancement of neutron-capture elements associated with
the rapid (r-) nucleosynthesis process that is responsible for
the production of the heaviest elements in the Universe. This
fortuity provides a unique opportunity of bringing together
astrophysics and nuclear physics because these objects act as
``cosmic lab'' for both fields of study. The so-called r-process
stars are thought to have formed from material enriched in heavy
neutron-capture elements that were created during an r-process
event in a previous generation SN. It appears that the few stars
known with this rare chemical signature all follow the scaled
solar r-process pattern (for the heaviest elements with $56