Dependence of s-process nucleosynthesis in massive stars on triple-alpha and 12C(α, γ)16O reaction rate uncertainties

Abstract

We have studied the sensitivity of s-process nucleosynthesis in massive stars to 2σ variations in the rates of the triple-α and 12C(α, γ)16O reactions. We simulated the evolution of massive stars from H burning through Fe-core collapse, followed by a supernova explosion. We found that the production factors of s-process nuclides between 58Fe and 96Zr change strongly with changes in the He burning reaction rates; using the Lodders solar abundances rather than those of Anders and Grevesse reduces s-process nucleosynthesis; later burning phases beyond core He burning and shell C burning have a significant effect on post-explosive production factors. We also discuss the implications of the uncertainties in the helium burning rates for evidence of a new primary neutron capture process (LEPP) in massive stars. © 2009. The American Astronomical Society. All rights reserved.