Astronomers have found a possible ‘zombie star’ about 110 million light years away using NASA’s Hubble Space Telescope. The zombie star might have been created during an unusually weak Type Iax supernova. Type Iax is a weaker, dimmer, smaller and less common type of explosion. The supernova, dubbed SN 2012Z, resides in the galaxy NGC 1309, which was discovered in the Lick Observatory Supernova Search in 2012.
What’s a zombie star?
What’s a zombie star, anyway? When white dwarf most stars explode, all of its gas, particles, dust and other matter is expelled into the space. That’s called Type Ia supernova, where little or nothing is left. There is also a less common, miniaturized version of supernova, leaving behind a surviving portion of the dwarf star. This is called Type Iax supernova, and the portion that survives is usually referred to as a zombie star. Type Iax is pretty rare. Scientists have so far spotted only 30 supernovae of this kind.
Rutgers University astronomer and lead author of the study Saurabh Jha said in a statement that Type Ia supernovae are important because they are used to measure cosmic distances and the expansion of the universe. For decades, researchers have been searching for star systems that produce Type Ia supernova. But they have never seen a Type Ia star before its explosion.
Discovery of the zombie star an important milestone
That’s why the discovery of this zombie star is considered even more important. Type Iax’s are closely related to the Type Ia’s. So, understanding the Type Iax progenitors will provide scientists clues about the Type Ia explosions. Astronomers analyzed Hubble images taken years before the supernova that gave birth to the zombie star.
They identified a white dwarf star sucking energy from a healthy blue companion star. The white dwarf star continued to feed off of its companion, which ignited a nuclear reaction leading to a weak supernova. Hubble had looked at this galaxy between 2005 and 2010. Researchers are waiting for the light of the supernova to fade so that they can take a closer look at the white dwarf.