Re-estimation of 180Ta nucleosynthesis in light of newly constrained reaction rates

Recent measurements of the nuclear level densities and γ-ray strength functions below the neutron thresholds in 180,181,182Ta are used as input in the nuclear reaction code TALYS. These experimental average quantities are utilized in the calculations of the 179,180,181Ta radiative neutron capture cross sections. From the latter, astrophysical Maxwellian-averaged (n,γ) cross sections (MACS) and reaction rates are extracted, which in turn are used in large astrophysical network calculations to probe the production mechanism of 180 Ta. These calculations are performed for two scenarios, the s-process production of 180,181Ta in Asymptotic Giant Branch (AGB) stars and the p-process nucleosynthesis of 180Tam in Type-II supernovae. Based on the results from this work, the s-process in stellar evolution is considered negligible in the production of 180Tam whereas 181Ta is partially produced by AGB stars. The new measurements strongly constrain the production and destruction rates of 180Tam at p-process temperatures and confirm significant production of nature’s rarest stable isotope 180Tam by the p-process.
SCOPUS: ar.j
info:eu-repo/semantics/published