Chemical Abundances for Evolved Stars in M5: Lithium through Thorium
  We present analysis of high-resolution spectra of a sample of stars in the
globular cluster M5 (NGC 5904). The sample includes stars from the red giant
branch (seven stars), the red horizontal branch (two stars), and the asymptotic
giant branch (eight stars), with effective temperatures ranging from 4000 K to
6100 K. Spectra were obtained with the HIRES spectrometer on the Keck I
telescope, with a wavelength coverage from 3700 to 7950 angstroms for the HB
and AGB sample, and 5300 to 7600 angstroms for the majority of the RGB sample.
We find offsets of some abundance ratios between the AGB and the RGB branches.
However, these discrepancies appear to be due to analysis effects, and indicate
that caution must be exerted when directly comparing abundance ratios between
different evolutionary branches. We find the expected signatures of pollution
from material enriched in the products of the hot hydrogen burning cycles such
as the CNO, Ne-Na, and Mg-Al cycles, but no significant differences within
these signatures among the three stellar evolutionary branches especially when
considering the analysis offsets. We are also able to measure an assortment of
neutron-capture element abundances, from Sr to Th, in the cluster. We find that
the neutron-capture signature for all stars is the same, and shows a
predominately r-process origin. However, we also see evidence of a small but
consistent extra s-process signature that is not tied to the light-element
variations, pointing to a pre-enrichment of this material in the protocluster
gas.
