The Hubble Space Telescope has spotted zombie stars, which are the remnants of a weak supernova explosion.
A supernova usually destroys the exploding star; however, researchers say that the zombie stars may have been left behind because the supernova was faint and not strong enough to destroy the star completely.
The faint supernova dubbed SN2012Z is located in galaxy NGC 1309, which the scientists report is about 110 million light-years away from the Earth. The supernova was initially discovered in Jan. 2012 by Lick Observatory Supernova Search. Researchers say that Hubble's Advanced Camera for Surveys too saw NGC 1309 for a few years before the supernova. This allowed scientists to compare the before images as well as the after images of the supernova.
Curtis McCully, lead author of the study and a graduate student at Rutgers University in Piscataway, New Jersey, studied the pre-explosion pictures and found a strange body close to the supernova location. McCully says that he was surprised to find an object near the supernova location. The scientists say that this supernova, classified as Type lax, is not very common when compared to the brighter supernova, Type la.
Saurabh Jha, a scientist at Rutgers University in Piscataway, New Jersey, reveals that for many decades scientists have been on the search of star systems, which produced supernovas, classified Type la. These types of supernova explosions are significant to astronomers as they are used as a measuring tool for cosmic distances as well as to help understand the expansion of our universe.
This is not the first time that astronomers have spotted a Type lax supernova using the Hubble Space Telescope. In 2013, scientists observed the outcome of a Type Iax supernova, dubbed SN 2008ha explosion. It is located in the UGC 12682 galaxy and is about 69 million light-years away.
"SN 2012Z is one of the more powerful Type Iax supernovae and SN 2008ha is one of the weakest of the class, showing that Type Iax systems are very diverse," says Ryan Foley of the University of Illinois at Urbana-Champaign, who is also the lead author of the paper on SN 2008ha. "And perhaps that diversity is related to how each of these stars explodes. Because these supernovae don't destroy the white dwarf completely, we surmise that some of these explosions eject a little bit and some eject a whole lot."
The researchers suggest that the latest finding will let them understand the connection between Type lax and Type la supernova better.