The mystery of the space object that emits radio signals every 18 minutes continues

(CNN) — While mapping radio waves in the universe, astronomers came across a space object that releases gigantic bursts of energy, unlike anything they’ve seen before.

The rotating space object, spotted in March 2018, emitted radiation three times an hour. At those times, it became the brightest source of radio waves visible from Earth, acting as a celestial beacon.

Astronomers think it could be a remnant of a collapsed star, either a dense neutron star or a dead white dwarf star, with a strong magnetic field, or it could be something else entirely.

A study of the discovery was published Wednesday in the academic journal Nature.

“This object appeared and disappeared over the course of a few hours during our observations,” lead study author Natasha Hurley-Walker, an astrophysicist at the Curtin University node of the International Center for Radio Astronomy Research, said in a statement.

“That was completely unexpected. It’s kind of puzzling to an astronomer because there’s nothing known in the sky that does that. And it’s very close to us, about 4,000 light-years away. It’s in our galactic backyard.”

Curtin University PhD student Tyrone O’Doherty made the unusual discovery while using the Murchison Widefield Array (MWA) telescope in the outback of Western Australia.

“It’s exciting that the source I identified last year turned out to be such a peculiar object,” O’Doherty said in a statement. “MWA’s wide field of view and extreme sensitivity are perfect for scanning the entire sky and detecting the unexpected.”

The Murchison Widefield Array captured the Milky Way at radio frequencies. The lowest frequencies are red, the middle ones are green, and the highest ones are blue. The star icon shows the mystery object.

What remains of the death of a massive star

Space objects that seem to turn on and off are known as transient objects.

“When you study transients, you are looking at the death of a massive star or the activity of the remnants it leaves behind,” said study co-author Gemma Anderson, an astrophysicist at ICRAR-Curtin, in a statement. ‘Slow transients’, such as supernovae, can appear within a few days and disappear after a few months. ‘Fast transients’, like a type of neutron star called a pulsar, turn on and off in milliseconds or seconds.”

However, this incredibly bright new object only stayed lit for one minute, every 18 minutes. The researchers said their observations could match the definition of an ultra-long-period magnetar. Magnetars or neutron stars with a strong magnetic field usually light up within seconds, but this object takes longer.

This is an artist’s impression of what the object might look like if it were a magnetar, or a neutron star with an incredibly strong magnetic field.

“It’s a type of slowly rotating neutron star whose existence has been predicted in theory,” Hurley-Walker said. “But no one expected to directly detect one like this because we didn’t expect it to be this bright. Somehow, it’s converting magnetic energy into radio waves much more efficiently than anything we’ve seen before.”

Investigators will continue to monitor the object to see if it turns back on, and in the meantime, look for signs of other similar objects.

“Further detections will tell astronomers whether this is a single, rare event or a vast new population that we’ve never noticed before,” Hurley-Walker said.