Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

Abstract

We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of $Z\lesssim 10^{-3}{Z}_{\odot }$. We find that for progenitors of $\sim 11$--$15{\mathrm{M}}_{\odot }$, the neutrons released by ${}^4\mathrm{He}({\bar{\nu }}_e,e^{+}n{)}^3\mathrm{H}$ in He shells can be captured to produce nuclei with mass numbers up to $A\sim 200$. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of ${}^9$Be in He shells. The first mechanism produces ${}^9$Be via ${}^7\mathrm{Li}(n,\gamma {)}^8\mathrm{Li}(n,\gamma {)}^9\mathrm{Li}(e^{-}{\bar{\nu }}_e{)}^9\mathrm{Be}$ and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of $\sim 8{\mathrm{M}}_{\odot }$, where ${}^9$Be can be produced directly via ${}^7\mathrm{Li}{(}^3\mathrm{H},n_0{)}^9\mathrm{Be}$ during the rapid expansion of the shocked He-shell material. The light nuclei ${}^7$Li and ${}^3$H involved in these mechanisms are produced by neutrino interactions with ${}^4$He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

6 pages, 3figures, OMEG 2015 conference proceedings, to appear in EPJ WOC proceedings

References in corpus (4)

• Production and evolution of Li, Be and B isotopes in the Galaxy
• A Long, Cold, Early r-process? Neutrino-induced Nucleosynthesis in He Shells Revisited
• Beryllium abundances in metal-poor stars
• New Primary Mechanisms for the Synthesis of Rare 9Be in Early Supernovae

Cited by in corpus (8)

• Origin of the Heaviest Elements: the Rapid Neutron-Capture Process
• Particle acceleration by supernova shocks and spallogenic nucleosynthesis of light elements
• Neutrinos and nucleosynthesis of elements
• Supernova Neutrino Process of Li and B Revisited
• An optimization-based approach to calculating neutrino flavor evolution
• Neutrinos, supernovae, and the origin of the heavy elements
• Novae: An Important Source of Lithium in the Galaxy
• Neutrinos and Heavy Element Nucleosynthesis