TO my understanding (based on this and this and my rusty old degree in astrophysics) there’s two types of systems that create type 1a supernovae
one is the double-degenerate model, where two white dwarfs eat each other and then both explode
the other is the single-degenerate model, where a white dwarf siphons off helium from a donor star, then it explodes and probably leaves the donor star more or less intact.
so, either you touch and you both go out in a blaze of destruction and creation, or you touch and one of you is destroyed... and the other has to live with it, in the cloud of debris they left, no less
but yeah either way it’s yuri