The white dwarf on the right is stealing matter from a neighbouring star. It will eventually explode as a type Ia supernova, propelling its companion away NASA/JPL-Caltech
Two white dwarfs rocketing through space are the fastest free-moving stars that we know about and they could explain how some supernovae form.
Type Ia supernovae are so reliably bright that astronomers use them as measuring sticks for assessing how far away distant stars and galaxies are. These supernovae tend to occur when a white dwarf siphons off matter from a neighbouring star and starts to swell, until it eventually becomes massive enough…
