A curious radio signal in space was spotted pulsing every 18 minutes and 18 seconds over a period of three months before it disappeared from view, revealing “an unusual periodicity” that has not been observed previously, reports kesq.com.
Astronomers think it might 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.
The object was discovered by a team using the Murchison Widefield Array (MWA) telescope in Western Australia, which scans large areas of the sky in radio waves.
“This object was appearing and disappearing over a few hours during our observations,” said Dr. Natasha Hurley-Walker, lead researcher on the study.
“That was completely unexpected. It was kind of spooky for an astronomer because there’s nothing known in the sky that does that. And it’s really quite close to us – about 4,000 light-years away. It’s in our galactic backyard.”
It pulsed with a regular rhythm, brightening for 30 to 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 pulse far faster, brightening and disappearing again in a matter of seconds.
“No one really thought of looking for objects on this timescale because we couldn’t think of any mechanisms that produce them, and yet they exist,” said Hurley-Walker.
Though the object was only visible to telescopes for a short time, its bizarre characteristics offer some tantalizing clues about its nature. Its radio pulses display strong linear polarization, which hints at the presence of ordered magnetic fields. It seems too bright to be a planet, and its light profile suggests that it is too compact to be a normal star.
The researchers will continue to monitor the object to see whether it turns back on, and in the meantime, they are searching for evidence of other similar objects.