Re-estimation of ¹⁸⁰ Ta 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 ^180,181,182 Ta are used as input in the nuclear reaction code TALYS. These experimental average quantities are utilized in the calculations of the ^179,180,181 Ta 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 ^180,181 Ta in Asymptotic Giant Branch (AGB) stars and the p-process nucleosynthesis of Tam180 in Type-II supernovae. Based on the results from this work, the s-process in stellar evolution is considered negligible in the production of Tam180 whereas ¹⁸¹ Ta is partially produced by AGB stars. The new measurements strongly constrain the production and destruction rates of Tam180 at p-process temperatures and confirm significant production of nature's rarest stable isotope Tam180 by the p-process.