“A clear indication that we may have something here.”

A radio signal from an Earth-sized exoplanet alerts a research team. The planet appears to have a magnetic field.

BOULDER – Researchers usually determine whether life is possible on an exoplanet by checking whether the temperatures there are suitable to allow liquid water to surface. However, there are other important criteria that a livable planet must meet. For example, the magnetic field is of great importance: it protects the planet’s atmosphere from high-energy particles and plasma thrown into space by the star around which the planet orbits.

If there was no magnetic field, the atmosphere would erode over time and disappear into space. “Whether or not a planet lives with an atmosphere can depend on whether or not the planet has a strong magnetic field,” University of Colorado astrophysicist Sebastian Pineda explains in one. communication. Together with Bucknell University astronomer Jackie Feldsen, Pineda has identified an Earth-sized planet outside our solar system that might have a magnetic field. The study was in the journal natural astronomy published.

An exoplanet is making signals – Researchers have doubts

YZ Ceti b is a rocky planet orbiting a star about 12 light-years from Earth. Pineda and Viladsen, while observing the planet, detected a repeating radio signal emanating from the star YZ Ceti. “I saw this thing that no one had seen before,” Villaadsen recalls the moment she first detected the radio signal. “We saw the first eruption and it looked great, and when we saw it again, it was a strong indication that we might actually have something here,” describes Pineda.

The research team suspects that the radio waves they detected are interactions between the magnetic field of an Earth-sized exoplanet and the star. These radio waves must be very powerful because of the great distance of twelve light years. To date, only Jupiter-sized exoplanets with magnetic fields have been discovered. To measure the magnetic fields around Earth-like planets, the team had to find a new method because magnetic fields are not directly visible, making it difficult to tell if a distant planet has it.

The exoplanet YZ Ceti b could have a magnetic field

Villadsen describes the technique the team used to search: “We’re looking for planets that are very close to their stars and similar in size to Earth. These planets are too close to their stars to live on, but because they’re so close, the planet kind of squirts through a bunch of emitted material.” of the star.” If the planet flies through enough stellar material, “make Stern emit bright radio waves,” Feldsen continues.

The red dwarf star YZ Cet and the exoplanet YZ Ceti b are a perfect match for this approach: the exoplanet is very close to its star — it only takes two days to orbit it once. The resulting radio waves are so powerful they can be observed on Earth. Among other things, researchers use them to measure the strength of a planet’s magnetic field.

The search for potentially habitable planets continues

“The search for potentially habitable or habitable worlds in other solar systems depends in part on whether rocky, Earth-like exoplanets do indeed have magnetic fields,” explains Joe Pesci, program director for the National Radio Astronomy Observatory at the National Science Foundation (NSF). . , which is leading the research is partially funded. “Not only does this research show that this particular rocky exoplanet likely has a magnetic field, but it also offers a promising way to find more.”