2007ApJ...671.1685M

Recent observations of r-process-enriched metal-poor star abundances reveal a nonuniform abundance pattern for elements Z≤47. Based on noncorrelation 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 nonuniformity. 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≤10¹³/cm3 or in the range n_n≥10²⁴/cm3 best explain the observations.