Roughly 3,000 light years away is a binary star system in the constellation Corona Borealis. As its name suggests, a binary star system consists of two stars. In this case, one is a large red giant star, and the other is a small, but incredibly dense white dwarf.

As they orbit each other, the red giant’s material gets sloughed off and falls into the white dwarf where it accumulates and heats up. The white dwarf then experiences a thermonuclear explosion — a nova — brightening to a point where we can see it with the unaided eye on Earth.