University of Sydney/European Southern Observatory
A star system in our galaxy could give us a ringside seat for one of the brightest lightshows in the universe. And, with luck, it won’t wipe out all life on our planet.
The system—located 8000 light-years away and dubbed Apep after an Egyptian snake deity—contains a binary pair of stars surrounded by a serpentine-shaped dust cloud. One of stars is an unusually massive sun known as a Wolf-Rayet star. When such stars run out of fuel, they collapse, causing a supernova explosion. Theorists believe that if the Wolf-Rayet star is also spinning fast, the explosion will produce intense jets of gamma rays out of either pole—which we can see far across the universe as a gamma ray burst, if we happen to be in the path of the beam.
Apep may be just such a case: Both stars are blowing off fast stellar winds; as the winds collide, they billow out in plumes of dust which, as the pair rotate, forms into the pinwheel pattern pictured above. Looking at the spectra of light from the system, the team found that wind is coming off the Wolf-Rayet star at a blistering 3400 kilometers per second, but that the dust plumes are moving at a more leisurely 570 kilometers per second. This is possible, they say in today’s issue of Nature Astronomy, if the Wolf-Rayet star is rotating rapidly and so producing fast wind at the pole and slower gusts at its equator. If the scientists are right, and this is a rapidly rotating Wolf-Rayet star, it could be the best candidate yet for a gamma ray burst in our own galaxy, although it may not blow for many thousands of years.
Theorists have suggested that if Earth happened to be lined up with such a nearby gamma ray blast, the intense ray of energy could wipe out our ozone layer or worse. But the team thinks Apep isn’t pointing in our direction. So enjoy the show and stay safe!