The minimum neutron star mass in neutrino-driven supernova explosions

TL;DR

This study uses 3D supernova simulations to establish a new lower limit for neutron star birth masses, finding a record-low mass close to observed values and suggesting such low masses are plausible in neutrino-driven supernovae.

Contribution

The paper provides the first 3D simulation-based lower limit for neutron star masses near the minimum for iron core collapse, refining theoretical constraints.

Findings

Record-low neutron star mass of 1.192 solar masses.

Neutron star kick velocity of approximately 100 km/s.

Residual uncertainties keep the observed 1.174 solar mass object plausible.

Abstract

Supernova theory has struggled to explain the lightest known neutron star candidate with an accurate mass determination, the $1.174\mathrm{M}_\odot$ companion in the eccentric compact binary system J0453+1559. To improve the theoretical lower limit for neutron star birth masses, we perform 3D supernova simulations for five stellar models close to the minimum mass for iron core collapse. We obtain a record-low neutron star mass of $1.192\mathrm{M}_\odot$ and a substantial kick of $\mathord{\sim} 100\,\mathrm{km}\,\mathrm{s}^{-1}$. Given residual uncertainties in stellar evolution, a neutron star origin for the $1.174\mathrm{M}_\odot$ object remains plausible.