A star system in the constellation Ophiuchus keeps blowing up. Every 15 years or so, it flares about 1500 times brighter than average. And it could be building up to an even bigger outburst – a final act that would make it shine billions of times brighter.

RS Ophiuchi consists of two stars. One of them is a white dwarf – a small, hot stellar corpse. The other is a red giant – a dying star that’s much bigger than the Sun.

Gas from the giant flows toward the white dwarf. It forms a swirling disk that’s millions of miles across. Gas in the disk spirals inward, and settles on the white dwarf. When enough gas builds up, it gets hot enough to trigger a nuclear explosion – a nova. Gas blasts outward at millions of miles an hour. That destroys the disk around the white dwarf – but only for a while. It regenerates in about nine months, starting the process all over again.

Astronomers have recorded as many as nine outbursts from the system – the first in 1898, the most recent just four years ago. The gap between them has ranged from nine to 27 years, with an average of about 15.

It’s possible that not all of the gas that piles up on the white dwarf gets blasted away, so the star keeps getting heavier. Eventually, it may pass the weight limit for such a star. If that happens, the white dwarf will blast itself to bits as a supernova – the final demise of a dead star.

Script by Damond Benningfield