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ESO originally published this article on June 2, 2026. Edits by EarthSky.
Magnetic exoplanets? Strange winds are strongest hint yet
A team of astronomers has found the strongest evidence yet that some planets outside our solar system might be magnetic.
Using the European Southern Observatory’s Very Large Telescope and the Gemini North telescope, the researchers measured wind speeds on seven very hot, Jupiter-like exoplanets. The observations revealed that the winds on these planets are most likely governed by magnetic fields, providing the first robust measurement of magnetism on planets outside the solar system.
Julia Seidel, lead author of the study, said:
This breakthrough opens a completely new window on exoplanet research. It’s the first time we can compare the magnetic environments of other worlds — a key step toward ultimately understanding which planets can stay alive, keep their water, and perhaps even, one day, host life as we know it.
The researchers published the peer-reviewed study in the journal Nature Astronomy on June 2, 2026.
Studying windy worlds
Earth’s magnetic field influences our atmosphere in complex ways. That makes it a key factor in understanding what keeps our planet habitable for life.
Magnetic fields are also present in other solar system planets, like Jupiter and Saturn. However, no one has yet succeeded in directly measuring the strength of the magnetic fields on planets outside our solar system.
The astronomers behind the research, however, didn’t set out to measure magnetic fields. Instead, they were interested in winds. They measured wind speeds on seven exoplanets orbiting different stars. They were all gas giants like Jupiter, but orbiting much closer to their stars than Jupiter does. Plus, they were all tidally locked, meaning the same side of the planet always faces the star. That results in a scorching hot day side and a freezing cold night side.
This temperature difference creates a climate completely different from the one on our planet, with extremely strong winds. The wind speeds in their sample ranged from around 4,500 mph (7,200 kph) to over 15,500 mph (25,000 kph). In comparison, the fastest winds measured on Jupiter have been around 930 mph (1,500 kph).
This animation from ESO shows how astronomers can infer the strength of exoplanet magnetic fields from how they affect wind speeds. Via ESO/ M. Kornmesser/ L. Calçada.
Strange winds point to magnetic exoplanets
The researchers initially set out to see if these winds behaved the same way for all hot planets. But when they looked at how the wind speeds varied with planet temperature, they saw a very intriguing pattern emerge: the hotter the planet, the slower the wind.
This was unexpected. Study co-author Vivien Parmentier said:
This is totally counter intuitive because, all things being equal, hot planets have more energy to accelerate the winds! Something must happen that slows down the wind speeds for hotter objects.
The team concluded that the most consistent explanation for this mystery is the presence of planet-wide magnetic fields. That’s because these fields can work as a brake, slowing down the motion of charged particles in the atmosphere.
The data therefore allowed the researchers to infer the strength of the magnetic field in each of the studied planets. They found them to be comparable in strength to those found in our solar system. They were approximately four times as strong as Saturn’s and about half the strength of Jupiter’s.
Powerful auroras on magnetic exoplanets?
Such strong magnetic fields could affect more than just the wind on these distant planets. Study co-author Bibiana Prinoth said:
Here on Earth, we know the beauty of the northern and southern lights, where particles from the sun hit our magnetic field and are guided toward the poles, colliding with gases in the atmosphere to produce colourful displays of green, pink and purple.
On the studied exoplanets, the magnetically driven auroras could be even more dramatic.
The team eagerly anticipates the arrival of ESO’s Extremely Large Telescope, which will help to characterize not only large, Jupiter-like exoplanets but also smaller ones like Earth. It could possibly even detect gases that could produce auroras on these distant worlds. Prinoth said:
I like to imagine that some of these worlds have a sky filled not only with stars, but with vast curtains of colourful light dancing across a planet that’s half in perpetual day and half in endless night.
Bottom line: Astronomers have found the strongest hint yet of magnetic exoplanets, thanks to new measurements of strange winds on distant worlds.
Read more: Powerful magnetic fields on super-Earths could boost chances of life
Watch: Jupiter’s auroras caught on film!