Transients from ONe White-Dwarf - Neutron-Star/Black-Hole Mergers

Understand

We conduct the first 3D hydrodynamic simulations of oxygen-neon white dwarf-neutron star/black hole mergers (ONe WD-NS/BH mergers).

• Such mergers constitute a significant fraction, and may even dominate, the inspiral rates of all WD-NS binaries.
• We post-process our simulations to obtain the nuclear evolution of these systems and couple the results to a supernova spectral synthesis code to obtain the first light curves and spectra for these transients.
• We find that the amount of $^{56}$Ni synthesised in these mergers grows as a strong function of the WD mass, reaching typically $0.05$ and up to $0.1\,{\rm M}_\odot$ per merger.