New Type of Supernova, 10 Times Brighter, Found by Scientists
A new class of supernova, 10 times brighter than previous explosions, may illuminate star-forming clouds in distant, primitive galaxies, enabling scientists to observe stellar creation.
Four of these exploding stars have been observed, according to a paper published in the journal Nature. Also, two previously unexplained events are now known to be this kind of supernova, the researchers said.
A supernova is the explosion of a massive star at the end of its life, when fuel is exhausted. If the star is large, the core collapses, releasing a burst of energy. The newly discovered explosions are 100 billion times brighter than the sun, said the study’s lead author, Robert Quimby, an astrophysicist at the California Institute of Technology in Pasadena.
“We didn’t know stars could blow up like this,” said Quimby in a telephone interview. “They’re brighter than entire galaxies.”
The new supernovas may also light up primitive galaxies, which would give astronomers the opportunity to see what an older universe looked like, Quimby said.
“Earlier in the universe, stars were more massive than they are now,” he said. “These may be very similar to the first supernova in the universe.”
The bigger a star is, the faster it burns fuel. A massive star begins by burning hydrogen, which is converted into helium by the reaction. After the helium is gone, the pressure in the star’s core will be sufficient to burn carbon and oxygen, leading to other elements forming.
In a traditional type II supernova, the star will continue burning elements until iron forms. Eventually, the entire star collapses inward, and an explosion occurs, blowing everything outside the core apart.
In the new type of supernova, the star is so large that it may not get as far as creating iron, Quimby said. The stars that produced the new type of supernovas were very large, and burned for only 3 million years. There may have been a runaway reaction at the oxygen stage, creating the explosion, he said.
“These stars partied hard,” Quimby said.
They are located in distant dwarf galaxies, which are a 10th the size of the Milky Way, the Earth’s galaxy. One of the explosions Quimby located was 5 billion light years away. Another was 8 billion light years.
A second study published in Nature today examined a more recent, closer supernova, SN1987A. After the initial explosion’s light faded from 1994 to 2001, X-rays led to a second wave of brightness, which more than doubled by the end of 2009.
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