Mysterious supernova in a class of its own

Astronomers believe helium was dragged from a companion star to the white dwarf, forming a shell that eventually became a supernova

Astronomers have discovered what they think is a new type of supernova, which could have implications for how the universe is measured.

Dr Dovi Poznanski of the University of California, Berkeley and colleagues, identified the supernova event in the galaxy NGC 1821, some 160 million light years away.

Dr Stuart Ryder, an astronomer with the Anglo Australian Observatory, says, "a lack of iron usually means the progenitor, a white dwarf, didn't explode completely, but simply ignited the material it had sucked up from its companion star, which is what a 'nova' does."