 A once-in-a-lifetime event. So is this like a supernova? Is that what you're describing? Good question. It's a little different. So a nova is a rapid increase in the brightness of a star. So in this case, T. coronae borealis is a binary star system, and that's made up of a white dwarf, that's a dead star about the size of Earth, and a red giant. So the white dwarf basically sucks material from the red giant, which causes a buildup of pressure and heat on the surface of the white dwarf, and eventually there's an explosion.