A radio signal from an Earth-sized exoplanet alerts a research team. Apparently the planet has a magnetic field.
Boulder — Researchers typically determine whether life is possible on an exoplanet by checking if temperatures there are appropriate to allow liquid water on the surface. However, there are other important criteria that a livable planet should meet. For example, a magnetic field is of great importance: it protects the planet’s atmosphere from the high-energy particles and plasma thrown into space by the star around which the planet orbits.
If there is no magnetic field, the atmosphere is eroded over time and disappears into space. “Whether or not a planet survives with an atmosphere can depend on whether or not the planet has a strong magnetic field,” explains University of Colorado astrophysicist Sebastian Pineda in one communication. Together with Jackie Villadsen, an astronomer at Bucknell University, Pineda has identified an Earth-sized planet outside our solar system that may have a magnetic field. The study was in the journal Nature Astronomy published.
Alien exoplanet emits signals – researchers have suspicions
YZ Ceti b is a rocky planet orbiting a star about 12 light-years from Earth. Pineda and Villadsen, while observing the planet, discovered a repeating radio signal emanating from the star YZ Ceti. “I saw this thing that nobody has seen before,” Villadsen recalls of the moment she first discovered the radio signal. “We saw the first eruption and it looked beautiful,” Pineda describes, continuing, “When we saw it again, it was a strong indication that we might actually have something here.”
|0.913 earth radii (estimated)|
The research team suspects that the radio waves they detected are interactions between the Earth-sized exoplanet’s magnetic field and the star. Such radio waves must be very strong because of the great distance of twelve light years. So far, only Jupiter-sized exoplanets with magnetic fields have been discovered. To measure magnetic fields around Earth-like planets, the team had to find a new method because the magnetic fields aren’t directly visible, making it difficult to tell if a distant planet has one.
Exoplanet YZ Ceti b could have a magnetic field
Villadsen describes the technique the team used to search: “We are looking for planets that are very close to their stars and are similar in size to Earth. These planets are far too close to their stars to live on, but because they’re so close, the planet is sort of plowing through a bunch of material coming off the star.” If the planet flies through enough star material, “it will Make Stern emit bright radio waves,” Villadsen continues.
Red dwarf star YZ Cet and exoplanet YZ Ceti b are a perfect match for this approach: the exoplanet is very close to its star – it takes only two days to orbit it once. The resulting radio waves are so strong that they can be observed on Earth. Among other things, the researchers use them to measure the strength of the planet’s magnetic field.
I saw this thing that nobody has seen before me.
Universe: Search for potentially habitable planets continues
“The search for potentially habitable or livable worlds in other solar systems depends in part on whether rocky, Earth-like exoplanets actually have magnetic fields,” explains Joe Pesce, program director of the National Radio Astronomy Observatory at the National Science Foundation (NSF), who is leading the research partially funded. “This research not only shows that this particular rocky exoplanet likely has a magnetic field, but also offers a promising way to find more.”
The research team is confident that YZ Ceti b is the best candidate yet for a rocky planet with a magnetic field. “But I think a lot of follow-up work will be needed before there’s really conclusive confirmation of the radio waves emitted by a planet,” Villadsen points out. Her colleague Pineda looks to the future with confidence: “There are many new radio systems that are being put into operation or are planned for the future. Once we have shown that this is really happening, we can approach it more systematically. We are still at the very beginning.” (tab)
This article was created with the help of machines and carefully checked by the editor Tanja Banner before publication.
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