Two suns 150 light years from Earth set to explode in blast 10x brighter than the Moon

Astronomers have identified an extremely rare, high-mass binary star system on a collision course just 150 light years from Earth—a discovery that could lead to one of the brightest cosmic events ever observed from our planet.

When the two dense stellar remnants, known as white dwarfs, finally merge, they will trigger a Type 1a supernova, a powerful thermonuclear explosion that scientists predict will shine nearly ten times brighter than the full Moon in our skies.

Published in the journal Nature, the study marks the first discovery of such a massive white dwarf pair within the Milky Way galaxy.

“For years a local and massive double white dwarf binary has been anticipated, so when I first spotted this system with a very high total mass on our Galactic doorstep, I was immediately excited,” said James Munday, the lead author of the study. “With an international team of astronomers, four based at The University of Warwick, we immediately chased this system on some of the biggest optical telescopes in the world to determine exactly how compact it is.”

The team used data from four ground-based telescopes to study the system. According to Munday, one white dwarf weighs in at 83% the mass of our Sun, while the other is about 72%—making this the highest combined mass ever recorded in a white dwarf binary.

"They are both about as big as the Earth," said Ingrid Pelisoli, co-author and astrophysicist at the University of Warwick. “One has a diameter about 20% larger and the other about 50% larger. That gives you an idea of how dense they are. It's the sun compressed onto the size of Earth.”

As the two stars spiral closer together, the more massive white dwarf will begin siphoning material from its companion. Once it passes a critical mass threshold, a runaway thermonuclear explosion will ensue—resulting in a catastrophic quadruple detonation.

This explosion will completely obliterate both stars, unleashing energy estimated to be a thousand trillion trillion times more powerful than the most potent nuclear bomb ever detonated.

Such events, known as Type 1a supernovae, are not only awe-inspiring but scientifically invaluable. They serve as cosmic “standard candles” used by astronomers to measure distances across the universe.