The Origins of Supernovae

The light from these stars is a little bit different from light from other supernova. They don't seem to have a lot of helium or hydrogen in their outer atmosphere. So that's one suspicion is that maybe they come from the heaviest of heavy stars. But we don't understand why not having hydrogen and not having helium would make the explosion brighter. Maybe there's some other reason that generates a bright supernova and happens to also remove the hydrogen and helium from the star. It's just like a clue we have found. We don't understand it yet.