The detection was achieved using the 64-dish MeerKAT radio telescope array in South Africa. A research team led by Kevin Ortiz Ceballos of the Center for Astrophysics | Harvard & Smithsonian analyzed data from four observing sessions conducted between February 2025 and May 2026. The array captured rapid radio bursts and weaker continuous background emissions. Through astrometric calibration, the team matched the exact position of the radio source to the orbit of Beta Pictoris b. Statistical checks confirmed the signal was distinct from the host star and the system’s other planets. This localization is the critical factor that distinguishes this finding from previous, unconfirmed hints of exoplanet radio activity, which could not definitively rule out the host star as the source.
The team attributes the signal to a mechanism known as electron cyclotron maser instability. This is the same physical process responsible for auroral radio emissions from Jupiter, Saturn, Uranus, and Neptune, as well as from certain brown dwarfs. In this process, energetic electrons stream along planetary magnetic field lines, generating highly concentrated radio waves. The detected bursts exhibited strong circular polarization, further confirming that magnetic forces drive the radiation. The highest frequency captured by the telescope indicates a local magnetic field strength of at least 1,250 gauss, or 0.125 kilogauss.
“In order to see radio waves that extend all the way to the frequencies that we observed, you need an incredibly strong magnetic field,” said Edo Berger, a professor of astronomy at Harvard University and co-author of the study.
For context, Earth’s surface magnetic field measures less than one gauss, while Jupiter’s magnetic field is powerful enough to generate the largest magnetosphere in our solar system. The inferred field strength of Beta Pictoris b is at least 200 times stronger than Jupiter’s. This measurement aligns closely with theoretical dynamo-scaling predictions for young, massive giant planets, providing a crucial benchmark for astrophysical models. The planet is approximately 12 times the mass of Jupiter and orbits its host star at a distance of roughly eight to ten astronomical units, depending on measurements of its 24-year orbit.
The Beta Pictoris system is estimated to be only 23 million years old, making it astronomically young compared to our solar system’s age of 4.5 billion years. The host star is described as magnetically quiet, which made the system an ideal target for isolating planetary signals. During one observation session in 2025, researchers noted two distinct radio bursts occurring roughly eight hours apart. This time gap matches the planet’s known rotation period, suggesting the emissions are linked to the planet’s spin. The planet was originally discovered in 2008, with two additional planets in the system identified in 2019 and 2026.
The findings, which constitute the first direct measurement of an exoplanet’s magnetic field, were posted to the arXiv preprint server on September 15 and are currently awaiting publication in a peer-reviewed journal. While the results are consistent with existing physical frameworks for magnetic dynamos, they remain provisional until formal peer review is completed. The detection offers a new observational window into the structure of exoplanet atmospheres and their interaction with stellar environments, moving beyond indirect inference to direct measurement of planetary magnetic properties.
