Astronomers have found a new kind of miniature supernova so comparatively small that some only shine a hundredth as brightly as their more common cousins. The newly-discovered stellar explosion is called a Type Iax supernova, and while the team that made the discovery still isn’t exactly sure what causes it, they’ve already identified 25 examples of the phenomenon, reports Space.com.
The white dwarf can actually survive the explosion
Like standard Type Ia supernovas, the new Type Iax variety also happen in binary systems, in which a white dwarf and companion star are locked in orbit around a common center of mass, and in both cases the white dwarf explodes. But surprisingly, in Type Iax supernovas the white dwarf can actually survive the explosion. "The star will be battered and bruised, but it might live to see another day," said lead researcher Ryan Foley. As far as what ultimately causes it to explode, it might be that the helium layer of the companion star ignites, detonating the white dwarf with a shock wave, or the white dwarf might ignite first due to the influence of its helium shell, which could alter the density and temperature of its interior.
It turns out that the new supernovas aren’t that rare, they’re just so faint that no one has noticed them until now. "For more than a thousand years, humans have been observing supernovas," said Foley. "This whole time, this new class has been hiding in the shadows."