The r-process in the early Galaxy
Abstract
We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant[Y/Zr] and [Sr/Y] values in the field stars places strong limits on the contributions of the weak s-process and the main s-process to the light neutron-capture elements. Stars in the globular cluster M 15 possess lower [Y/Zr] values than the field stars. There is a large dispersion in [Y/Ba]. Because the r-process is responsible for the production of the heavy elements in the early Galaxy, these dispersions require varying light-to-heavy ratios in r-process yields.
Cite
@article{arxiv.astro-ph/0208375,
title = {The r-process in the early Galaxy},
author = {Jennifer A. Johnson and Michael Bolte},
journal= {arXiv preprint arXiv:astro-ph/0208375},
year = {2009}
}
Comments
10 pages, 5 color figures, to be published in ApJ