The remnants of an exploded star, a white dwarf of a type sometimes dubbed a "zombie star," may have been observed some 110 million light-years away from Earth, astronomers say.
Using the Hubble Space Telescope, astronomers have detected a star pairing they say may have created such a "zombie star" following an untypically weak explosion of a supernova.
In Hubble images obtained before the explosion, a blue companion star was seen feeding material to a nearby white dwarf, an activity that subsequently initiated a nuclear reaction resulting in a weaker supernova blast known as a Type Iax, NASA astronomers say.
Surviving portions of a white dwarf, sometimes seen after such weak explosions, have been nicknamed "zombie stars" -- not quite completely dead, not quite "alive."
More than 30 of this type of weak supernovas that may have left a white dwarf survivor have been identified, astronomers say.
Type Iax supernovae are much less common than their brighter Type Ia cousins, in which the white dwarf is typically entirely obliterated, they say.
"Astronomers have been searching for decades for the star systems that produce Type Ia supernova explosions," says Saurabh Jha of Rutgers University.
As the light from the supernova dubbed SN 2012Z fades, astronomers will use the Hubble telescope during 2015 to get a better look at the surviving white dwarf and possibly its contributing companion star as well.
"Usually during a supernova, a white dwarf would just be totally gone," study co-author and astrophysicist Curtis McCully says. While the case is an interesting one for many scientists, experts are still puzzling over the question of why the companion star may have changed if it lived through the violent cosmic event.
The surviving zombie star is in the galaxy NGC 1309, where the supernova was detected in January of 2012. Hubble images taken for a number of years before the supernova explosion have allowed the astronomers to compare some before-and-after images.
"Back in 2009, when we were just starting to understand this [supernova] class, we predicted these supernovae were produced by a white dwarf and helium star binary system," says researcher Ryan Foley of the University of Illinois at Urbana-Champaign.
The scientists who are studying the curious star admit to certain uncertainties regarding the situtaion. However, the existence of the star may validate their previous claims.
