Astronomers have discovered a new form of 'mini' supernova 'hiding in the shadows' of space.
Supernovas normally occur when massive stars run out of fuel and collapse in upon themselves into an extremely dense core in a fraction of a second. The resultant explosion can be seen across the universe, and can light up the sky on Earth.
But these explosions can also occur when a white dwarf locked in an orbit with another star siphons too much mass from its companion.
The new 'mini' supernova is similar to this second type, but is far fainter.
Known as a Type Iax supernova, they shine only a hundredth as brightly as the larger type.
"[This] is essentially a mini-supernova," said lead researcher Ryan Foley, an astronomer at the Harvard-Smithsonian Center for Astrophysics, to Space.com.
"It's the runt of the supernova litter."
It is still unclear exactly what is happening in the supernova, the team said. But it appears that the helium in the companion star's shell undergoes nuclear fusion, blasting a 'shock wave' towards the other star, causing it to explode. It is also possible that the material taken from one star alters the chemistry of the larger one, resulting in a massive explosion.
Interestingly, the new type of supernova isn't necessarily fatal for the star. The white dwarf may actually survive the Iax explosion, Foley said.
"The star will be battered and bruised, but it might live to see another day," Foley said. "We're not quite sure why only part of the star might get destroyed. That's a tough problem we're working on right now."
"For more than a thousand years, humans have been observing supernovas. This whole time, this new class has been hiding in the shadows."