The signal did not come from the star. For the first time, astronomers say they can pin a radio detection on an exoplanet itself, and the world in question is Beta Pictoris b, a giant roughly 10 times the mass of Jupiter, first discovered in 2008.
A team from the Center for Astrophysics Harvard & Smithsonian and the University of Oregon announced the result. It is not a message. The bursts are thought to come from the planet’s auroras, the same kind of process that makes the northern and southern lights on Earth, where charged particles interact with an atmosphere and a magnetic field and release energy.
Finding the source
Earlier radio detections around planet-hosting stars could not be separated from the stars themselves. As the researchers put it in their paper, “no radio detection has previously been unambiguously localized to an extrasolar planet rather than its host star.”
The team used the MeerKAT array in South Africa, observing on four occasions in 2025 and 2026 across frequencies from 0.85 to 3.5 GHz. Their target was Beta Pictoris, a star about 63.4 light-years away with three known planets. What came back were short, repeating bursts of strongly circularly polarized radio waves, a classic auroral signature.
To show which body was transmitting, the researchers used quasars, the super-bright cores of distant galaxies, as reference points in their sky map. That placed the source on planet b. The star is an early-type star, hotter and bigger than the Sun, and the team wrote that “no physical mechanism known to cause radio emission in early-type stars can explain the observed emission.”
A measurement of a magnetic field
The emission fits the Electron Cyclotron Maser Instability, the process behind auroras on Earth and Jupiter. It also carries information. The researchers describe the result as “the first direct measurement of magnetic field strength for an exoplanet,” consistent with predictions for a young, massive giant. They calculate a field thousands of times stronger than Earth’s, possibly powered by a rotation of only 8 to 9 hours.
The team now has seven other known giant planets in five nearby star systems on its list. Next-generation radio observatories, with an expected 5x to 7x gain in sensitivity, should bring them within reach, the researchers write. The work has not yet passed peer review and is posted on arXiv.
