Scientists raise eyebrows at repeating signal from nearby Earth-sized planet

Astronomers have detected signals from an Earth-sized exoplanet that is just 12 light years away from Earth, according to the results of a new study published in the scientific journal Nature Astronomy.

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The exoplanet astronomers have identified is called YZ Ceti b, and it orbits a red dwarf star within the constellation Cetus. NASA notes on its website that this exoplanet is a rocky world that's approximately the size of Earth with a mass of 0.7 Earths. Other notable features of YZ Ceti b are its orbit which is the time it takes for it complete one full rotation around its host star. According to the space agency and the astronomers in their paper, YZ Ceti b only takes two Earth days to complete one orbit of it star.

The team behind the paper detected multiple repeating radio signals from YZ Ceti b, which leads researchers to suggest that this exoplanet may have a magnetic field, and by extension, perhaps an atmosphere. It should be noted that detecting an exoplanet's magnetic fields has proven quite difficult for astronomers, which is unfortunate considering it's a vital element in how life has managed to survive and thrive on Earth.

"I'm seeing this thing that no one has seen happen before. If the planet has a magnetic field and it plows through enough star stuff, it will cause the star to emit bright radio waves," said study co-author Jackie Villadsen

A magnetic field is a crucial piece of life's puzzle as it provides the necessary protection for the planet to survive blasts of charged particles in the form of Coronal Mass Ejections (CME), solar flares, and basically, anything else stars spew out into their surrounding location. Without a magnetic field, the planet is slowly stripped away, leaving no atmosphere and, therefore, no life as humans know it.

The interaction between charged particles from a star and the magnetic field of a planet produces radio waves that can be detected by researchers. The produced radio waves form the phenomena called an aurora or the Northern or Southern Lights. The team behind the study looked at YZ Ceti b and detected bright radio waves around the host star. From these detected radio waves, the team is able to determine the strength of the exoplanet's magnetic field.

"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. This research shows not only that this particular rocky exoplanet likely has a magnetic field but provides a promising method to find more," said Joe Pesce, program director for the National Radio Astronomy Observatory

According to lead author Sebastian Pineda, an astrophysicist at the University of Colorado, when the researchers detected these signals, they were actually seeing an aurora on the host star, which Pineda says would have also been present on YZ Ceti b if it has an atmosphere.

The quest to find a second Earth continues, and with each study such as this, the boundary of what humans know about our galactic neighborhood is extended.