What would happen if there was a collision between 2 white dwarfs (or any other super compact objects), especially if their combined mass would not create a black hole? Would the two be destroyed? If they are destroyed, what would be left?
The current consensus (of many) is that two white dwarfs is one mechanism to cause a Type Ia supernova, a massive explosion that would completely destroy both progenitor objects. Much of the mass is converted into luminous energy, as supernovae often briefly outshine the rest of the host galaxy it would be in. Some particles are also ejected in the explosion, such as atomic nuclei, neutrons, etc. The nuclei will collide with one another, and become bombarded by neutrons, converting them into different elements. The majority of the heavy elements beyond iron are formed by this mechanism.
This page was last updated February 10, 2016.