# Electron-Capture and Low-Mass Iron-Core-Collapse Supernovae: New Neutrino-Radiation-Hydrodynamics Simulations

## TL;DR

This study uses new 1D and 2D simulations to explore electron-capture and low-mass iron-core-collapse supernovae, revealing conditions for explosion and the significant role of PNS convection in neutrino emission.

## Contribution

The paper provides detailed simulations of various progenitors, demonstrating the ease of explosion in ECSN-like models and highlighting the underestimated impact of PNS convection.

## Key findings

- ECSN and ECSN-like progenitors explode easily in 1D with low energies.
- 9-11 solar mass progenitors do not explode in 1D and are not easier in 2D.
- PNS convection can double neutrino luminosity, affecting supernova dynamics.

## Abstract

We present new 1D (spherical) and 2D (axisymmetric) simulations of electron-capture (EC) and low-mass iron-core-collapse supernovae (SN). We consider six progenitor models: the ECSN progenitor from Nomoto (1984, 1987); two ECSN-like low-mass low-metallicity iron core progenitors from Heger (private communication); and the 9-, 10-, and 11-$M_\odot$ (zero-age main sequence) progenitors from Sukhbold et al. (2016). We confirm that the ECSN and ESCN-like progenitors explode easily even in 1D with explosion energies of up to a 0.15 Bethes ($1 {\rm B} \equiv 10^{51}\ {\rm erg}$), and are a viable mechanism for the production of very low-mass neutron stars. However, the 9-, 10-, and 11-$M_\odot$ progenitors do not explode in 1D and are not even necessarily easier to explode than higher-mass progenitor stars in 2D. We study the effect of perturbations and of changes to the microphysics and we find that relatively small changes can result in qualitatively different outcomes, even in 1D, for models sufficiently close to the explosion threshold. Finally, we revisit the impact of convection below the protoneutron star (PNS) surface. We analyze, 1D and 2D evolutions of PNSs subject to the same boundary conditions. We find that the impact of PNS convection has been underestimated in previous studies and could result in an increase of the neutrino luminosity by up to factors of two.