Astronomers have uncovered an extraordinary discovery in the cosmos: a binary star system consisting of two white dwarf stars, located just 150 light-years away from Earth. These stars are on a collision course, destined to explode in a Type 1a supernova—a cosmic event that will outshine the moon itself by up to ten times.
A Rare and Tightly Bound Binary System
The pair of white dwarfs, discovered by astronomers at the University of Warwick, are locked in a tight orbit, bringing them closer together with each passing day. The two stars are separated by a mere 1/60th of the Earth-Sun distance, a proximity that will eventually result in their catastrophic collision.
According to the study published in Nature, this is the first confirmed binary white dwarf system of its kind to be observed in our galaxy, adding significant weight to the theory that Type 1a supernovae typically arise from such systems.
What Happens in a Type 1a Supernova?
A Type 1a supernova occurs when a white dwarf, the dense remnant of a star that has exhausted its nuclear fuel, accrues enough mass from a nearby companion to trigger an explosive event.
This explosion is one of the most energetic phenomena in the universe, and Type 1a supernovae are crucial for measuring cosmic distances due to their predictable luminosity.
In this case, the explosion of the binary system will be particularly bright, estimated to be ten times more luminous than the moon, and visible across vast stretches of space.
Tracking the Discovery
James Munday, a PhD researcher at Warwick University and leader of the study, was thrilled to spot the system.
“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,” Munday said.
The team of international astronomers immediately began observing the system with some of the most powerful optical telescopes in the world. Their observations revealed that the two stars were on a collision course, with their masses combining to form the heaviest double white dwarf system ever discovered, weighing in at 1.56 times the mass of our Sun.
A Bright and Distant Event
The supernova is expected to occur approximately 23 billion years from now—an event far beyond the span of human existence. While the system is relatively close in astronomical terms, it poses no danger to Earth.
“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,” Munday explained.
Their observations have provided rare insight into a binary system on the brink of a distant, spectacular explosion, offering a valuable window into the long-term evolution of stellar remnants.