Astronomers have recorded radio emissions originating directly from a planet outside our solar system for the first time, according to findings detailed in a preprint study shared by researchers from the Center for Astrophysics | Harvard & Smithsonian and the University of Oregon. While past observations of distant star systems captured radio signals, researchers were previously unable to definitively separate planetary emissions from the much brighter radio noise generated by host stars. The team used the MeerKAT radio telescope array in South Africa to monitor the Beta Pictoris star system on four separate occasions across 2025 and 2026.
First Unambiguous Radio Signal Detected From an Exoplanet
By utilizing distant, highly magnetized galactic cores known as quasars as fixed reference points, scientists successfully triangulated and isolated the source of the transmissions. The data revealed rapid, repeating, and strongly circularly polarized radio bursts alongside persistent emissions at frequencies ranging from 0.8 to 3.5 GHz. The target of the observations was Beta Pictoris b, a young gas giant located approximately 63.4 to 64 light-years from Earth.
Auroral Origins and Natural Phenomena
Although technosignatures and signals from intelligent extraterrestrial civilizations are a primary focus of groups searching the cosmos, researchers emphasized that the newly detected transmissions are entirely natural. The characteristics of the radio waves indicate that the signal stems from powerful auroras on the exoplanet, comparable to the northern and southern lights observed on Earth and Saturn but on a vastly larger scale.
The emissions are generated via a physical process called electron cyclotron maser instability, or ECMI. This mechanism occurs when energetic charged particles interact with a planet’s upper atmosphere and magnetic field. Because known physical mechanisms governing hot, massive stars like the A6V-class Beta Pictoris cannot account for the observed frequencies, the researchers concluded the signals must originate from the orbiting gas giant.
Direct Calculation of Planetary Magnetic Field Strength
The ability to detect and analyze these auroral radio bursts allowed the research team to calculate the strength of the exoplanet’s magnetic field. Because the frequency of ECMI-driven radio emission is directly tied to the magnetic-field strength at its source, the detection of bursts up to 3.5 GHz enabled the first direct measurement of an exoplanet’s magnetic field.
The team estimated Beta Pictoris b’s magnetic field to be roughly 1,250 gauss, or 1.25 kilogauss—thousands of times stronger than Earth’s magnetic field and hundreds of times stronger than Jupiter’s. This measurement aligns with existing dynamo-scaling predictions for young, massive giant planets that complete a rapid rotation in roughly eight to nine hours.
Future Implications for Exoplanet Research
The successful localization of radio waves to a specific extrasolar world opens a new avenue for studying the internal properties and atmospheric shielding of distant planets. A planet’s magnetic field serves as a critical barrier, protecting its atmosphere from the continuous stellar wind of charged particles emitted by its host star.
While the current findings remain preliminary and await peer review, the research team is already looking toward other giant exoplanets across nearby star systems. Astronomers anticipate that upcoming instrumentation—such as the Square Kilometre Array, for which MeerKAT functions as a pathfinder—will offer significantly greater sensitivity and enable the detection of similar signals from smaller planets in the future.