(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 shields the planet’s atmosphere, which life needs to survive, by scattering energetic particles and plasma streaming in from the sun. Finding atmospheres around planets outside our solar system could point to other worlds that could potentially support life.
Scientists noticed strong radio waves coming from the star YZ Ceti and the rocky exoplanet it orbits, called YZ Ceti b, during observations with the Karl G. Jansky Very Large Array of Telescopes in New Mexico. Researchers believe that the radio signal was generated by interactions between the planet’s magnetic field and the star.
Detailed study results were Published Monday in the journal natural astronomy.
“We saw the initial eruption and it looked beautiful,” said Sebastian Pineda, senior author of the study, a research. University of Colorado Boulder astrophysicist, in a statement. “When we saw it again, it was very indicative that, well, maybe we really have something here.”
Magnetic fields could prevent the planet’s atmosphere from diminishing and essentially eroding over time as particles shoot off the star and bombard it, Pineda said.
How do strong radio waves occur?
For radio waves to be detectable on Earth, the researchers said, they would have to be very powerful.
“Whether or not a planet stays in the atmosphere can depend on whether or not the planet has a strong magnetic field,” Pineda said.
Previously, researchers had detected magnetic fields on exoplanets similar in size to Jupiter, the largest planet in our solar system. But finding magnetic fields on smaller planets is much more difficult because magnetic fields are essentially invisible.
Study co-author Jackie Feldsen, assistant professor of physics and astronomy at Bucknell University, said: Pennsylvania in a statement.
“We are looking for planets that are very close to their stars and are similar in size to Earth,” she said. “These planets are too close to their stars to be anywhere you can live, but because they’re so close, the planet kind of gets through a bunch of stuff coming off the star. If the planet has a magnetic field and enough stellar stuff passes through it, This will cause bright radio waves to be emitted from the star.”
It takes YZ Ceti b only two Earth days to complete one orbit around its star. Meanwhile, the shortest orbit in our solar system is the planet Mercury, which takes 88 Earth days to complete a revolution around the Sun.
As YZ Ceti b orbits its star, the star’s plasma collides with the planet’s magnetic field, bouncing back and interacting with the star’s magnetic field. All of these energetic interactions create and emit powerful radio waves that can be detected on Earth.
This illustration depicts the plasma emitted from a star deflected by the magnetic field of an orbiting exoplanet. The plasma then interacts with the star’s magnetic field, producing auroras and radio waves.
The researchers measured the radio waves they detected to determine the strength of the planet’s magnetic field.
“This tells us new information about the environment around stars,” Pineda said. “This idea is what we call ‘extrasolar space weather.'” “
In our solar system, activity on the Sun can create space weather that affects Earth. Active explosions from the sun can disrupt global satellites and communications and cause dazzling light shows near the Earth’s poles, such as the aurora borealis or northern lights.
Scientists imagine that interactions between YZ Ceti and its planet also create aurorae, but this light show actually happens on the star.
“We’re actually seeing the aurora borealis on the star — that’s what this radio broadcast is about,” Pineda said. “There should also be aurorae on the planet if it had its own atmosphere.”
Rocky exoplanet candidate
Researchers believe that YZ Ceti b is the best candidate observed so far for a rocky exoplanet with a magnetic field.
“This could be a really reasonable thing to do,” Viadsen said. “But I think there will be a lot of follow-up work before there is really strong confirmation of planet-induced radio waves.”
New radio telescopes poised for operation this decade could help astronomers make more detections of signals indicating magnetic fields, researchers said.
Joe Pesci, program director for the National Astronomical Observatory, said in a statement. “This research shows not only that this particular rocky exoplanet likely has a magnetic field but provides a promising way to find more.”
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