Repeating radio signal leads astronomers to an Earth-size exoplanet

(CNN) Astronomers have detected a repeating radio signal from an exoplanet and the star it orbits, both located 12 light years from Earth. The signal suggests that the Earth-sized planet may have a magnetic field and possibly even an atmosphere.

Earth’s magnetic field protects the planet’s atmosphere, which life needs to survive, by deflecting energetic particles and plasma flowing from the sun. Finding atmospheres around planets located outside our solar system could indicate other worlds that potentially have the ability to support life.

Scientists spotted strong radio waves coming from the star YZ Ceti and the rocky exoplanet orbiting it, called YZ Ceti b, during observations using the Karl G. Jansky Very Large Telescope Array in New Mexico. Researchers believe the radio signal was created by interactions between the planet’s magnetic field and the star.

A study detailing the findings was published Monday in the journal Nature Astronomy.

“We saw the initial burst and it looked beautiful,” lead study author Sebastian Pineda, a research astrophysicist at the University of Colorado Boulder, said in a statement. “When we saw it again, it was very indicative that, OK, maybe we really have something here.”

Magnetic fields can prevent a planet’s atmosphere from shrinking and essentially corroding over time as particles are ejected from the star and bombard it, Pineda said.

How strong the radio waves appear

In order for radio waves to be detectable on Earth, they must be very strong, the researchers said.

“Whether or not a planet survives with an atmosphere may depend on whether or not the planet has a strong magnetic field,” Pineda said.

Previously, researchers have detected magnetic fields in exoplanets similar in size to Jupiter, the largest planet in our solar system. But finding magnetic fields on smaller Earth-sized planets is more difficult because magnetic fields are essentially invisible.

“What we’re doing is looking for a way to see them,” study co-author Jackie Villadsen, assistant professor of physics and astronomy at Bucknell University in Pennsylvania, said in a statement.

“We’re looking for planets that are really close to their stars and are similar in size to Earth,” she said. “These planets are too close to their stars to be habitable, but because they’re so close, the planet is plowing through a bunch of stuff coming out of the star. If the planet has a magnetic field and it goes through enough star, will cause the star to emit bright radio waves.”

YZ Ceti bi takes just two Earth days to complete a single orbit around its star. Meanwhile, the shortest orbit in our solar system is the planet Mercury, which takes 88 Earth days to orbit the sun.

As YZ Ceti b orbits its star, plasma from the star collides with the planet’s magnetic field, bounces off and interacts with the star’s magnetic field. All of these energetic reactions create and emit strong radio waves that can be detected on Earth.

This illustration depicts plasma emitted by a star deflected by the magnetic field of the exoplanet orbiting it. The plasma then interacts with the star’s magnetic field, creating an aurora and radio waves.

The researchers measured the radio waves they detected to determine the strength of the planet’s magnetic field.

“This is telling us new information about the environment around stars,” Pineda said. “This idea is what we’re calling ‘extrasolar space weather’.”

In our solar system, activity on the sun can create space weather that affects Earth. Energetic bursts from the sun can disrupt satellites and global telecommunications and cause dazzling light displays near Earth’s poles, such as the aurora borealis, or northern lights.

Scientists imagine that interactions between YZ Ceti and its planet also create an aurora, but this light show actually occurs in the star.

“We’re actually seeing the aurora in the star — that’s what this radio show is,” Pineda said. “There must also be auroras on the planet if it has its own atmosphere.”

Rocky exoplanet candidate

The researchers think that YZ Ceti b is the best candidate observed so far for a rocky exoplanet with a magnetic field.

“That could be really plausible,” Villadsen said. “But I think it’s going to be a lot of follow-up work before there’s really strong confirmation of radio waves caused by a planet.”

New radio telescopes set to become operational this decade could help astronomers make more discoveries of signals that suggest magnetic fields, researchers said.

“The search for potentially habitable or life-supporting worlds in other solar systems depends in part on being able to determine whether rocky, Earth-like exoplanets actually have magnetic fields,” said Joe Pesce, program director for the National Astronomical Observatory of Radio Astronomy. a statement. “This research shows not only that this particular rocky exoplanet likely has a magnetic field, but offers a promising method to find more.”