# Sub-Chandrasekhar-mass white dwarf detonations revisited

## TL;DR

This paper revisits simulations of sub-Chandrasekhar-mass white dwarf detonations, providing new nucleosynthetic data and comparing results with observations to assess their role as Type Ia supernova progenitors.

## Contribution

It offers updated nucleosynthetic yields and light curve models for bare C/O white dwarf detonations, challenging previous findings and supporting the double detonation scenario.

## Key findings

- A 1.0 Msol WD detonation produces a median-brightness SN Ia.
- Simulated nucleosynthesis broadly agrees with some observational constraints.
- Synthetic light curves and spectra are roughly consistent with observed SNe Ia.

## Abstract

The detonation of a sub-Chandrasekhar-mass white dwarf (WD) has emerged as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. Recent studies have suggested that the rapid transfer of a very small amount of helium from one WD to another is sufficient to ignite a helium shell detonation that subsequently triggers a carbon core detonation, yielding a "dynamically-driven double degenerate double detonation" SN Ia. Because the helium shell that surrounds the core explosion is so minimal, this scenario approaches the limiting case of a bare C/O WD detonation. Motivated by discrepancies in previous literature and by a recent need for detailed nucleosynthetic data, we revisit simulations of naked C/O WD detonations in this paper. We disagree to some extent with the nucleosynthetic results of previous work on sub-Chandrasekhar-mass bare C/O WD detonations; e.g., we find that a median-brightness SN Ia is produced by the detonation of a 1.0 Msol WD instead of a more massive and rarer 1.1 Msol WD. The neutron-rich nucleosynthesis in our simulations agrees broadly with some observational constraints, although tensions remain with others. There are also discrepancies related to the velocities of the outer ejecta and light curve shapes, but overall our synthetic light curves and spectra are roughly consistent with observations. We are hopeful that future multi-dimensional simulations will resolve these issues and further bolster the dynamically-driven double degenerate double detonation scenario's potential to explain most SNe Ia.