Nucleosynthesis in the Early Galaxy

Abstract

Recent observations of r-process-enriched metal-poor star abundances reveal a non-uniform abundance pattern for elements $Z\le 47$. Based on non-correlation trends between elemental abundances as a function of Eu-richness in a large sample of metal-poor stars, it is shown that the mixing of a consistent and robust light element primary process (LEPP) and the r-process pattern found in r-II metal-poor stars explains such apparent non-uniformity. Furthermore, we derive the abundance pattern of the LEPP from observation and show that it is consistent with a missing component in the solar abundances when using a recent s-process model. As the astrophysical site of the LEPP is not known, we explore the possibility of a neutron capture process within a site-independent approach. It is suggested that scenarios with neutron densities $n_n\le 10^{13}$ $c{m}^{-3}$ or in the range $n_n\ge 10^{24}$ $c{m}^{-3}$ best explain the observations.

28 pages, 7 Postscript figures. To be published in The Astrophysical Journal

References in corpus (6)

• Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars
• Neutron-capture elements in the very metal-poor star HD122563
• The rp-Process in Neutrino-driven Winds
• Neutron-capture elements in the very metal-poor star HD88609: another st ar with excesses of light neutron-capture elements
• Supernova Fallback: A Possible Site for the r-Process
• Neutron-capture elements in the metal-poor globular cluster M15

Cited by in corpus (5)

• The s process in massive stars at low metallicity. Effect of primary N14 from fast rotating stars
• Beta-decay half-lives and beta-delayed neutron emission probabilities of nuclei in the region below A=110, relevant for the r-process
• Mass measurements beyond the major r-process waiting point 80Zn
• Dependence of S-Process Nucleosynthesis in Massive Stars on Triple-Alpha and 12C(a,g)16O Reaction Rate Uncertainties
• Fission Cycling in a Supernova r-process