On Type Ia supernovae from the collisions of two white dwarfs

We explore collisions between two white dwarfs as a pathway for making Type Ia supernovae (SNIa). White dwarf number densities in globular clusters allow 10-100, redshift less than or similar to 1 collisions per year, and observations by Chomiuk et al. of globular clusters in the nearby S0 galaxy NGC 7457 have detected what is likely to be a SNIa remnant. We carry out simulations of the collision between two 0.6M(circle dot) white dwarfs at various impact parameters and mass resolutions. For impact parameters less than half the radius of the white dwarf, we find such collisions produce approximate to 0.4M(circle dot) of(56)Ni, making such events potential candidates for underluminous SNIa or a new class of transients between Novae and SNIa.