Researchers May Have Directly Glimpsed an Exoplanet’s Magnetic Field for the First Time, Building Hope of Peering Deeper Into Faraway Worlds

From our corner of the big and complicated universe, it can be difficult to see worlds beyond the solar system in detail. Lots of fuzz can get in the way of observing faraway exoplanets: Earth’s semi-opaque atmosphere, the glare of other solar system’s stars and, of course, the sheer fact of distance. Astronomers may have discovered more than 6,000 exoplanets, but only bare minimum information, such as mass, radius and maybe some of the molecules dotting their surface, is understood about most.

Now, scientists may have discovered another detail. For the first time, researchers have directly detected the magnetic field of a large exoplanet about 63 light years away, by tracking radio bursts and buzzes. The team’s preprint paper, which has not yet been peer-reviewed, was posted to arXiv.org on September 15.

The exoplanet, dubbed Beta Pictoris b, was found to have a magnetic field of around 2,000 times that of Earth. By imaging the planet at various radio wavelengths, the scientists found a pattern of radio signals that suggested an auroral spectacle—though likely a more extreme show than our mild-mannered northern lights. If these conclusions hold up in peer review, “this would be a slam dunk,” says Joe Callingham, a radio astronomer at the Netherlands Institute for Radio Astronomy, who was not involved in the study.

Magnetic fields encase most of our solar system’s planets and are generated by planetary rotation combined with hot, electric inner activity. Earth’s magnetic bubble is often lauded as key to our planet’s habitability. By deflecting gusty solar winds to our poles, it shields us from a direct attack from these charged particles.

Strong magnetic fields can also have downsides: As stellar remnants accelerate toward a planet’s poles, the energy delivered may cause the planet to lose mass, according to Jackie Villadsen, an astronomer at Bucknell University. How to build a planetary magnetic field By studying magnetic fields in planets beyond our solar system, scientists hope to probe exoplanets’ inner structures, paint a clearer picture of planetary evolution and someday build a stronger measure for the probability of life on other planets. But making progress on these goals has proven to be a challenge.

But they have been known to dazzle at radio wavelengths, putting out signals suggestive of magnetic activity. Perhaps, Berger’s team thought, our universe’s largest gas giants—which can closely resemble brown dwarfs—would behave similarly. If they, too, spewed out radio emissions, astronomers could finally directly image planetary magnetic fields.