Main point: Astronomers found a “lost” young-looking supernova, PS1-12sk, in an old galaxy with the help of Pan-STARRS telescope on Haleakala in Hawaii.
Journal: The research has been submitted to The Astrophysical Journal.
Study further: Astronomers have classified PS1-12sk under rare type Ibn supernova, i.e. so rare that it is only sixth example from thousands of different supernovae. This supernova is present in a bright elliptical galaxy about 780 million light-years away from us. You can see the brightly shining elliptical galaxy near the center of the above image with a yellow dot (circled) at the image center.
“It could be that we simply got very lucky with this discovery,” said Alicia Soderberg of the CfA. “But luck favors the prepared.”
Researchers are not clear about the origin of this supernova but a massive star that expelled a huge amount of helium gas is thought to be the cause of this supernova. They proposed this origin as the previously found five supernova explosions of the huge stars were also found in the spiral galaxies such as our Milky Way, where a number of new stars are constantly forming – new stars constantly formed old stars constantly explodes. Another supposition of the formation of this supernova is that the collision of two white dwarfs, one of which was rich in helium, result in the formation of PS1-12sk supernova.
PS1-12sk is not a common type of supernova as the site of the explosion doesn’t show any signs of star formation and the supernova of this type has not been found in elliptical galaxies before this time.
“This supernova is one of a kind,” said Nathan Sanders of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts. “And it’s definitely in the wrong neighborhood.”
Moreover, this finding shows that the host galaxy may have a number of other hidden stars.
“Is this a runaway star from another star formation site?” asked John Tonry from the University of Hawaii Institute of Astronomy. “Is it a very local bit of star formation? Is it a different way for such a supernova to occur? None of these seems very likely, so we have a real puzzle.”