This infrared view of supernova remnant RCW 86 highlights the dusty remains of all that’s left of an ancient supernova that’s thousands of years old: the earliest documented example of a supernova visible in our night sky. It happens to be a type Ia supernova, but no surviving companion has ever been found. (Credit: NASA/JPL-Caltech/UCLA)

Ask Ethan: Can companion stars survive a supernova?

If stars don’t go supernova at first, they can get a second chance after becoming a white dwarf. But can their companions survive?

In all the Universe, few events are as energetic as the violent, explosive death of a star or stellar corpse: a supernova. While some supernovae are triggered by massive stars reaching the end of their lives, others are triggered when a stellar corpse of a star that wasn’t quite massive enough to go supernova the first time — a white dwarf — gains enough mass to cross over a critical threshold into unstable territory: above the limit where it can remain a white dwarf. When such an event occurs, the white dwarf violently explodes, creating the second most common class of supernova: a type Ia supernova, or as I sometimes call it, a “second chance” supernova.

But that mass has to come from somewhere, and that’s almost always from another star or stellar corpse near the white dwarf: a companion star. While a type Ia supernova always destroys the white dwarf that initiated it, the companion can undergo many possible fates. How can we know what will happen to it? That’s what Denise Selmo wants to know, inquiring:

“I am writing this to ask you a question about Supernovae type 1a. So, when the dwarf…