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

Malatji, K.L.  (iThemba LABS, P.O. Box 722, Somerset West, 7129, South Africa) (Physics Department, University of Stellenbosch, Matieland, 7602, South Africa) ; Wiedeking, M. (iThemba LABS, P.O. Box 722, Somerset West, 7129, South Africa) ; Goriely, S.  (Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, CP 226, Brussels, B-1050, Belgium) ; Brits, C.P. (iThemba LABS, P.O. Box 722, Somerset West, 7129, South Africa) (Physics Department, University of Stellenbosch, Matieland, 7602, South Africa) ; Kheswa, B.V. (iThemba LABS, P.O. Box 722, Somerset West, 7129, South Africa) (Department of Applied Physics and Engineering Mathematics, University of Johannesburg, Johannesburg, 2028, South Africa) ; Bello Garrote, F.L. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Bleuel, D.L. (Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA) ; Giacoppo, F. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) (Helmholtz Institute Mainz, Mainz, 55099, Germany) (GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, 64291, Germany) ; Görgen, A. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Guttormsen, M. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Hadynska-Klek, K. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Hagen, T.W. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Ingeberg, V.W. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Klintefjord, M. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Larsen, A.C.  (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Papka, P. (iThemba LABS, P.O. Box 722, Somerset West, 7129, South Africa) (Physics Department, University of Stellenbosch, Matieland, 7602, South Africa) ; Renstrøm, T. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Sahin, E. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Siem, S. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Siess, L. (Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, CP 226, Brussels, B-1050, Belgium) ; Tveten, G.M. (Department of Physics, University of Oslo, Oslo, N-0316, Norway) ; Zeiser, F. (Department of Physics, University of Oslo, Oslo, N-0316, Norway)

12 March 2019

Abstract: 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.


Published in: Physics letters B (2019)
Published by: Elsevier
DOI: 10.1016/j.physletb.2019.03.013
License: CC-BY-3.0



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