The minimum neutron star mass in neutrino-driven supernova explosions

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.