  We have investigated the abundances of heavy neutron-capture elements,
including osmium (Os) and iridium (Ir), in the two Carbon-Enhanced Metal-Poor
(CEMP) subgiants CS31062-050 and LP625-44. CS31062-050 is known to be a
so-called CEMP-r/s star, which exhibits large excesses of s-process elements
such as barium (Ba) and lead (Pb), as well as a significant enhancement of
europium (Eu) that cannot be explained by conventional s-process production in
Asymptotic Giant Branch star models. Our analysis of the high-resolution
spectrum for this object has determined, for the first time, the abundances of
Ir and Os, elements in the third peak of the r-process nucleosynthesis. They
also exhibit significant excesses relative to the predictions of standard
s-process calculations. These two elements are not detected in a
similar-quality spectrum of LP625-44; the derived upper limits on their
abundances are lower than the abundances in CS31062-050. We compare the
observed abundance patterns of neutron-capture elements, including Os and Ir,
in these two stars with recent model calculations of the s-process, and discuss
possible interpretations.
