Double Degenerate Collisions and Mergers

Cody Raskin
Arizona State University


Using conservative estimates of white dwarf number densities in globular clusters allows for 10-100 direct collisions between two white dwarfs per year at redshift < 1. We have recently conducted a comprehensive simulation study of white dwarf collisions as an avenue for creating type Ia supernovae. We examined the resulting 56Ni yield as a function of total mass, mass ratio, and impact parameter. Several combinations of white dwarf masses and impact parameters are able to produce sufficient quantities of 56Ni to be observable at cosmological distances. The 56Ni production in double-degenerate white dwarf collisions ranges from sub-luminous to the super-luminous, depending on the parameters of the collision. Double degenerate mergers are also explored with special attention paid to the sensitivity of the final outcomes to initial conditions and to the shear heating of the core-disk interface of the merger remnants.