Astronomers have discovered a "really weird" object 4,000 lightyears away from Earth, a study published in Nature on Wednesday said. The object disappears from view every other minute and emits a giant burst of radio waves three times an hour.
The mysterious object was first seen by Curtin University student Tyrone O'Doherty when he was observing the sky in outback Western Australia. "It's exciting that the source I identified last year has turned out to be such a peculiar object," O'Doherty said in a press release.
The object, which the astronomers say is unlike anything else they've discovered, sends out a massive beam of radiation that, every 20 minutes, becomes one of the brightest in the sky. It also spins and disappears every other minute.
Space objects that "turn" on and off in the night sky are called "transients" by scientists, and they're relatively common.
"When studying transients, you're watching the death of a massive star or the activity of the remnants it leaves behind," ICRAR-Curtin astrophysicist and co-author of the study Dr. Gemma Anderson said.
Slower transients, such as supernovae, can appear in a few days and stick around for a couple of months.transients, like some neutron stars, "flash" on and off multiple times in a second. But transients in between those two speeds are rare, and the latest discovery — in the words of the astronomers — is "really weird" and "completely unexpected."
"It was kind of spooky for an astronomer because there's nothing known in the sky that does that," said astrophysicist Dr. Natasha Hurley-Walker, who led the team of scientists. "And it's really quite close to us — about 4000 lightyears away. It's in our galactic backyard."
Hurley-Walker described the mysterious object as smaller than the sun but bright, and emitting highly-polarized radio waves three times an hour. These radio pulses indicate that it has an "extremely strong" magnetic field — and may match a predicted astrophysical object that has never been proven to exist. Scientists call the theoretical object an "ultra-long period magnetar."
"It's a type of slowly spinning neutron star that has been predicted to exist theoretically," Hurley-Walker said. "But nobody expected to directly detect one like this because we didn't expect them to be so bright. Somehow it's converting magnetic energy to radio waves much more effectively than anything we've seen before."
The astronomers currently believe that it may be a rare type of neutron star or a collapsing white dwarf, but they need to observe it again to determine if it is a fluke or a new type of space object.