Radio waves

Neutron stars: a mysterious object emits radio waves every 18 minutes

Something extraordinarily bright in space is pulsating much slower than most similar cosmic objects, and it may be a strange kind of neutron star we’ve never seen before

Space out

January 26, 2022

A view of the Milky Way from the Murchison Widefield Array. The star-shaped icon indicates the position of the mysterious pulsating object

Dr Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM team

A mysterious object in space is vibrating in a way astronomers have never seen before. It may be a strange neutron star – the remnant of a massive star that exploded. Examining celestial objects like this could help us understand the agony of the stars.

Natasha HurleyWalker at Curtin University in Perth, Australia, and his colleagues found this object using the Murchison Widefield Array (MWA), an Australian radio telescope. After spotting a barrage of radio waves that seemed to appear and then disappear, they dug through archival data taken by the MWA in early 2018 and found an additional 71 pulses.

With each pulse, the object – named GLEAM-X J162759.5-523504.3 and located about 4,000 light-years away – released huge amounts of energy. “The brightness here is really crazy – really, really, really extreme,” Hurley-Walker said at a press conference. “We didn’t expect to find something so brilliant.”

It pulsed at a steady rate, lighting up for 30-60 seconds once every 18.18 minutes. Nothing with a rhythm similar to this has been found before – most flashing radio objects in the sky pulsate much faster, lighting up and disappearing again within seconds. “Nobody really thought about looking for objects on this timescale because we couldn’t think of any mechanism that produced them, and yet they exist,” Hurley-Walker said.

The pulsation indicates that the object is probably rotating, and other measurements of its light suggest that it must have a strong magnetic field. This led researchers to suspect it could be a magnetar, a type of neutron star with a particularly strong magnetic field, but it’s unclear how a magnetar could spin so slowly and shine so brightly.

“I was worried it might be extraterrestrials, but…it’s over a very wide frequency range, and that means it must be a natural process – it’s not an artificial signal,” he said. said Hurley-Walker. She and her colleagues are now looking for more objects like this so we can figure out what they are.

Journal reference: Nature, DOI: 10.1038/s41586-021-04272-x

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