Supernovae from Collapse of Oxygen-Magnesium-Neon Cores

The collapse of degenerate oxygen-magnesium-neon cores produces supernovae that are sensitive to the characteristics of both hydrodynamical bounce and nuclear burning. The authors report the results of a numerical study of the collapse of such a core. An explosion is produced primarily via late-time neutrino heating, and not by prompt exit of the shock wave formed after core bounce. Explosion energies are in the range (0.6 - 1.2)×10⁵¹ergs. For models with the larger energy, a neutron star remnant is formed with a gravitational mass of about 1.2 M_sun;. If the outer hydrogen-helium envelope originally surrounding the core has been lost prior to collapse and the collapsing object is a bare white dwarf, a neutron star remnant can be produced without a spectacular optical display.