Supernova eats white dwarfs

"Two astronomers in the US have found a Type 1a supernova that did not leave behind a surviving companion star after it exploded. Instead, they conclude that the supernova was caused by two white-dwarf stars colliding and then both stars being consumed in the conflagration. Although the observation is of just a single supernova, the discovery adds weight to the theory that at least some Type 1a supernovae are the result of such collisions."

in PhysicsWorld