Convective-reactive nucleosynthesis of K, Sc, Cl and p-process isotopes in O-C shell mergers

C. Ritter, R. Andrassy, B. Côté, F. Herwig, P. R. Woodward, M. Pignatari, S. Jones

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36 Scopus citations


We address the deficiency of odd-Z elements P, Cl, K and Sc in Galactic chemical evolution models through an investigation of the nucleosynthesis of interacting convective O and C shells in massive stars. 3D hydrodynamic simulations of O-shell convection with moderate C-ingestion rates show no dramatic deviation from spherical symmetry. We derive a spherically averaged diffusion coefficient for 1D nucleosynthesis simulations, which show that such convective-reactive ingestion events can be a production site for P, Cl, K and Sc. An entrainment rate of 10-3M s-1 features overproduction factors OPs ≈ 7. Full O-C shell mergers in our 1D stellar evolution massive star models have overproduction factors OPm > 1 dex but for such cases 3D hydrodynamic simulations suggest deviations from spherical symmetry. γ - process species can be produced with overproduction factors of OPm > 1 dex, for example, for 130, 132Ba. Using the uncertain prediction of the 15M⊙, Z = 0.02 massive star model (OPm ≈ 15) as representative for merger or entrainment convective-reactive events involving O- and C-burning shells, and assume that such events occur in more than 50 per cent of all stars, our chemical evolution models reproduce the observed Galactic trends of the odd-Z elements.

Original languageEnglish (US)
Pages (from-to)L1-L6
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - Feb 1 2018

Bibliographical note

Publisher Copyright:
© 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.


  • Galaxy: abundances
  • Physical data and processes: hydrodynamics
  • Stars: abundances
  • Stars: evolution
  • Stars: interiors


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