Nucleosynthesis in the Innermost Ejecta of Magnetorotational Supernova Explosions in Three Dimensions

Abstract

Core-collapse supernova (CCSN) explosions powered by rotation and magnetic fields present an interesting astrophysical site for nucleosynthesis that potentially contributes to the production of r -process elements. Here we present yields of the innermost ejecta in 3D magnetorotational CCSN models simulated using the CoCoNuT-FMT code. Strong magnetic fields tap the rotational energy of the proto−neutron star and lead to earlier and more energetic (∼3 × 10 ^51 erg) explosions than typical neutrino-driven CCSNe. Compared to a reference nonmagnetic model, the ejecta in the magnetorotational models have much more neutron-rich components with Y _e down to ∼0.25. Our post-processing calculations with the reaction network SkyNet show significant production of weak r -process elements up to mass number ∼130. We find negligible differences in the synthesis of heavy elements between two magnetorotational models with different initial field strengths of 10 ^10 and 10 ^12 G, in accord with their similar explosion dynamics. The magnetorotational models produce about ∼0.19 and 0.14 M _☉ of radioactive ^56 Ni, on the low end of inferred hypernova nickel masses. The yields are publicly available at Zenodo (doi: 10.5281/zenodo.10578981) for comparison with stellar abundance patterns, inclusion in modeling galactic chemical evolution, and comparison with other yield calculations. Our results add to the yet-restricted corpus of nucleosynthesis yields from 3D magnetorotational supernova simulations and will help quantify yield uncertainties.

Keywords

• Core-collapse supernovae
• Magnetohydrodynamics
• Nucleosynthesis
• R-process