A planet’s magnetic field can shield its atmosphere from particles spewed out by its star. The fact that a planet has a strong magnetic field can affect the possibility that it can support life with an atmosphere.
Now, astronomers have discovered one exoplanet as a leading candidate to also have a magnetic field: YZ Ceti b. Located about 12 light-years from Earth, YZ Ceti b orbits a star YZ Ceti. Scientists have observed a repeating radio signal emanating from the star using the Karl G. Jansky Very Large Array, a radio telescope operated by the US National Science Foundation’s National Radio Astronomical Observatory.
Jackie Villadsen, an astronomer at Bucknell University, said: “I’m seeing something that no one has seen happen before.” He remembers the moment: when he isolated the radio signal while reviewing data at home over the weekend. Sebastián Pineda, an astrophysicist at the University of Colorado, said: “We saw the initial burst, and it looked beautiful. When we saw it again, it told us that, okay, we might have something here.” Interactions between the exoplanet’s magnetic field and the star it orbits are believed to be the source of the stellar radio waves astronomers discovered. However, these radio waves must be very powerful in order to be picked up over great distances. Although magnetic fields have already been discovered on giant Jupiter-sized exoplanets, a different method is needed to do so on a relatively small Earth-sized exoplanet.
The small red dwarf star YZ Ceti and its known exoplanet, YZ Ceti b, were an ideal match because the exoplanet is so close to the star that it completes a full orbit in just two days. When YZ Ceti’s plasma breaks away from the planet’s magnetic “plough,” it interacts with the star’s own magnetic field, generating radio waves strong enough to be observed on Earth.
The small red dwarf star YZ Ceti and its known exoplanet, YZ Ceti b, were an ideal match because the exoplanet is so close to the star that it completes a full orbit in just two days. When YZ Ceti’s plasma breaks away from the planet’s magnetic “plough,” it interacts with the star’s own magnetic field, generating radio waves strong enough to be observed on Earth.
Pineda said: “We see the aurora on the star – that’s what this radio emission is. There should also be an aurora on the planet if it has its atmosphere.” “Both researchers agree that although YZ Ceti b is the best candidate so far for a rocky exoplanet with a magnetic field, it is not a closed case. It is plausible that it is this one. But I think there will be a lot of follow-up work before one appears.” really solid confirmation of radio waves being caused by a planet.”
Sources, credits and references: National Science Foundation – Sebastian Pineda, Coherent radio bursts from known M-dwarf planet-host YZ Ceti, Nature Astronomy (2023). DOI: 10.1038/s41550-023-01914-0.https://www.nature.com/articles/s41550-023-01914-0