The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

N. Nishimura, H. Sawai, T. Takiwaki, S. Yamada, F. K. Thielemann

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

We investigated r-process nucleosynthesis in magneto-rotational supernovae, based on a new explosion mechanism induced by the magneto-rotational instability (MRI). A series of axisymmetric magnetohydrodynamical simulations with detailed microphysics including neutrino heating is performed, numerically resolving the MRI. Neutrino-heating dominated explosions, enhanced by magnetic fields, showed mildly neutronrich ejecta producing nuclei up to A ∼ 130 (i.e., the weak r-process), while explosion models with stronger magnetic fields reproduce a solar-like r-process pattern. More commonly seen abundance patterns in our models are in between the weak and regular r-process, producing lighter and intermediate-mass nuclei. These intermediate r-processes exhibit a variety of abundance distributions, compatible with several abundance patterns in r-processenhanced metal-poor stars. The amount of Eu ejecta ∼ 10-5 M. in magnetically driven jets agrees with predicted values in the chemical evolution of early galaxies. In contrast, neutrino-heating dominated explosions have a significant amount of Fe (56Ni) and Zn, comparable to regular supernovae and hypernovae, respectively. These results indicate magneto-rotational supernovae can produce a wide range of heavy nuclei from iron-group to r-process elements, depending on the explosion dynamics.

Original languageEnglish
Article numberL21
JournalAstrophysical Journal Letters
Volume836
Issue number2
DOIs
Publication statusPublished - 2017 Feb 20

Keywords

  • gamma-ray burst: general
  • magnetohydrodynamics (MHD)
  • neutrinos
  • nuclear reactions, nucleosynthesis, abundances
  • stars: neutron
  • supernovae: gene

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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