A “coherent” radio signal has been detected from an alien planet, suggesting it could be more likely to be habitable.
The signal suggests that the planet has its own magnetic field, which is thought to be central to sustaining life on a particular world.
On Earth, our magnetic field helps protect us from the high energy particles and plasma that are blasted from the Sun. As such, any alien life is likely to depend on being protected by a similar field.
But until now researchers have struggled to confirm whether distant rocky planets have magnetic fields of their own, and therefore have found it difficult to say how likely a planet might be to able to support life.
Now the new candidate – YZ Ceti b, a rocky planet that orbits a star about 12 light years away – has sent a repeating radio signal that comes from the star and seems to be affected by the planet.
The radio waves the researchers detected from the planet appear to be generated when the star interacts with its planets’ magnetic field. Because the two of them are so close together, the new candidate is an ideal pair to test theories about whether those magnetic fields could be detectable at such a distance.
Researchers described the effect as similar to the aurora borealis, or northern lights, which happens on Earth when high energy particles from the Sun interact with our planet’s atmosphere.
“We’re actually seeing the aurora on the star — that’s what this radio emission is,” said Sebastian Pineda, an astrophysicist at the University of Colorado and one of the researchers who saw the signal. “There should also be aurora on the planet if it has its own atmosphere.”
“The search for potentially habitable or life-bearing worlds in other solar systems depends in part on being able to determine if rocky, Earth-like exoplanets actually have magnetic fields,” said Joe Pesce, program director for the National Radio Astronomy Observatory. “This research shows not only that this particular rocky exoplanet likely has a magnetic field but provides a promising method to find more.”
The findings are described in a new paper, ‘Coherent radio bursts from known M-dwarf planet-host YZ Ceti’, published in Nature Astronomy.