Supernovae are the universe's most powerful explosions. Scientists have been studying them not only to understand the life cycles of stars, but also because their origins could help explain how many of the heavy elements in our universe were created.
Supernovae can be formed in different ways, and now, scientists have finally observed a Type 1A supernova where a companion red giant star feeds gas to a white dwarf star - resulting in a final, brilliant explosion.
The discovery is exciting for scientists because while all Type 1A supernovae are similar and can be used to measure distances across the universe, this event shows that they can originate from different circumstances.
"By comparison, our observations last year of another Type 1a supernova progenitor system called SN 2011fe, showed no evidence of a red giant," said study co-author Dr. Andy Howell from Las Cumbres Observatory Global Telescope Network.
"How could these events look so similar, if they had different origins?" he asks.
The Type 1A supernova, PTF 11kx, is the first one observed supernova where a white dwarf star accumulated enough mass to go supernova.
Typically, novae are produced when a white dwarf star accumulates gas and matter from a companion red giant star. These smaller novae cause the white dwarf star to lose mass, or so scientists thought.
Supernova PTF 11kx, on the other hand, underwent at least two of these smaller novae, before finally ending with a massive supernovae.
Type 1A supernovae are incredibly rare, happening around once or twice every 100 years. The version observed by the scientists with a red giant is even rarer.
"You maybe find one of these systems in a sample of 1,000 Type 1a supernovae," says Peter Nugent, who first observed supernova PTF 11kx, from Lawrence Berkeley National Laboratory.