University of Warwick astronomers have discovered an extremely rare, high-mass, compact binary star system only ~150 light years away. These two stars are on a collision course to explode as a type 1a supernova, appearing 10 times brighter than the moon in the night sky.

Type 1a supernovae are a special class of cosmic explosion, famously used as “standard candles” to measure distances between Earth and their host galaxies. They occur when a white dwarf (the dense remnant core of a star) accumulates too much mass, is unable to withstand its own gravity, and explodes.

It has long been theoretically predicted that two orbiting white dwarfs are the cause of most type 1a supernova explosions. When in a close orbit, the heavier white dwarf of the pair gradually accumulates material from its partner, which leads to that star (or both stars) exploding.