Astronomers from the United States say they've discovered a new class of supernova that doesn't fit in the two previously known categories.
The new class of supernova has been dubbed Type Iax.
Astronomers had previously divided supernovae into two types, known as core-collapse and Type Ia. Core-collapse supernovae are caused by the explosion of a star about 10 to 100 times the size of the sun, while Type Ia supernovae are the result of the complete explosion of a tiny white dwarf.
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The new Type Iax class of supernova is fainter and less energetic than the Type Ia and is thought to be the result of a white dwarf star explosion, which did not destroy the star entirely.
"A Type Iax supernova is essentially a mini supernova," lead study author Ryan Foley of the Harvard-Smithsonian Center for Astrophysics said. "It's the runt of the supernova litter."
Type Iax supernovae are about one-hundredth as bright as other supernovae and are around a third as common as the Type Ia supernovae. The new class of supernova is also thought to come from young star systems, as it was not found in elliptical galaxies, which are filled with older stars.
Foley and his colleagues identified 25 examples of the new type of supernova. The research has been accepted for publication in the Astrophysical Journal.