A rotating binary star system, WR 104, 8,000 light-years from Earth, thought to be the final stage of stellar evolution to precede a cataclysmic supernova explosion, could emit a gamma ray burst toward Earth, astronomers at the University of Sydney have found.

A 2005 study showed that a gamma-ray burst originating within 6,500 light-years of Earth could be enough to strip away the ozone layer and cause a mass extinction.