New research has revealed the source of repeated radio signals emulating from space, first picked up two years ago.
In 2022, a team of astronomers picked up on intense bursts of radio waves repeatedly emitting from space, however, they remained baffled as to where it was coming from and what was causing it.
And they've since been able to track one of the signals back to its original source.
The original discovery
Tasked with looking for radio sources that were changing, in 2020, undergraduate student Tyrone O'Doherty discovered a 'particularly unusual source that was visible in data from early 2018, but had disappeared within a few months,' Stephen Khan explained in an article for The Conversation.
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Questioning whether the source - named GLEAM-X J162759.5-523504 - could be an exploded star or a sign of a collision in space, Khan dove deeper into investigating it in 2022.
The team found the source would emit signals every 18 minutes with 'exactly the same frequency' - it was 'like nothing astronomers had ever seen before'.
While identifying the signal was from a natural source and that the source of the radio waves likely had a 'strong magnetic field' located 'less than half a second across, much smaller than our Sun', astronomers still couldn't work out exactly where GLEAM-X J162759.5-523504 was coming from - until now.
Tracing the radio signal back to its source
The team began a new project, using the Murchison Widefield Array radio telescope in Western Australia to scan the sky for radio waves - 'which can observe 1,000 square degrees of the sky every minute'.
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The telescope found a new source - GLEAM-X J0704-37 - which pulses out radio waves for a minute every 2.9 hours.
The MeerKAT telescope in South Africa then helped pinpoint where these radio waves were coming from.
And voila! The suspect? A red dwarf star - although, not quite.
Explanation behind the radio waves
Red dwarf stars are the most common type of star in the Milky Way but aren't visible to the naked eye.
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Combining data from the Murchison Widefield Array and MeerKAT telescopes, the team resolved that it was likely not the red dwarf star itself emitting the radio waves but 'an unseen object in a binary orbit with it'.
Khan said: "Based on previous studies of the evolution of stars, we think this invisible radio emitter is most likely to be a white dwarf, which is the final endpoint of small to medium-sized stars like our own Sun. If it were a neutron star or a black hole, the explosion that created it would have been so large it should have disrupted the orbit."
Basically, the red dwarf can produce charged particles similar to those produced by the Sun. These charged particles then hit the white dwarf's magnetic field, which Khan explained 'would be accelerated, producing radio waves'.
Poppy Bilderbeck