Astronomers have observed a repeated signal emerging from the star YZ Ceti, which they believe is generated by the interactions between the magnetic field of the exoplanet and the star it orbits. What excites them is the strength of these signals, which are strong given the wide distance between Earth and the rocky planet.
“I’m seeing this thing that no one has seen happen before. We saw the initial burst and it looked beautiful. When we saw it again, it was very indicative that, OK, maybe we really have something here,” Jackie Villadsen, who observed the signal said.
Magnetic field
A computer-generated visualization of solar wind interacting with Earth’s magnetic field during a powerful solar storm. (Photo: Advanced Visualization Lab, National Center for Supercomputing Applications)
The signals were observed using the Karl G. Jansky Very Large Array, a radio telescope operated by the U.S. National Science Foundation.
The signals spark hope for a habitable world since the planet’s magnetic field can prevent that planet’s atmosphere from being worn away over time by particles spewed from its star. Earth’s magnetic field works in a similar fashion, preventing dangerous cosmic rays from the Sun from hitting it directly.
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“Whether a planet survives with an atmosphere or not can depend on whether the planet has a strong magnetic field or not,” Sebastian Pineda, an astrophysicist at the University of Colorado, added.
Since magnetic fields are invisible, it’s challenging to determine if a distant planet actually has one. Astronomers are looking for Earth-sized planets that are really close to their stars, at a distance that can support life. “Because they are so close, the planet is kind of plowing through a bunch of stuff coming off the star. If the planet has a magnetic field and it plows through enough star stuff, it will cause the star to emit bright radio waves,” Villadsen explained.
The observed planet YZ Ceti b is so close to its star that it completes a full orbit in only two days and as plasma from YZ Ceti interacts with the magnetic field, it generates radio waves strong enough to be observed on Earth.
Astronomers also speculate that interactions between YZ Ceti b and its star also produce an aurora, but with a significant difference: The aurora is on the star itself.