Astronomers have detected radio emissions coming directly from an exoplanet for the first time, opening a new way to study the magnetic fields and internal structures of worlds beyond the Solar System.

The signals came from Beta Pictoris b, a young gas giant orbiting a star approximately 63 light-years from Earth. The planet is several times more massive than Jupiter and belongs to a planetary system estimated to be about 23 million years old, making it extremely young compared with the 4.6-billion-year-old Solar System.

The signals are not evidence of extraterrestrial communication. They are natural radio emissions produced by charged particles interacting with the planet’s powerful magnetic field, similar to the auroral radio bursts generated by Jupiter and other magnetised planets.

Researchers detected the emissions using MeerKAT, an array of 64 radio dishes in South Africa. Their observations revealed rapid and recurring bursts between frequencies of 0.85 and 3.5 gigahertz, alongside a weaker but more persistent radio glow.

The bursts were highly circularly polarised, meaning the radio waves rotated in a consistent direction as they travelled through space. This is a distinctive feature of a process known as electron cyclotron maser emission, in which electrons moving through a magnetic field release intense beams of radio energy.

Astronomers had previously detected radio signals from star systems known to contain planets, but they were generally unable to determine whether the emissions originated from the planet, its host star or an interaction between the two. Beta Pictoris b is different because it orbits far enough from its star for the MeerKAT observations to locate the radio source at the planet’s position.

The planet’s movement provided further confirmation. Researchers conducted multiple observations as Beta Pictoris b travelled along its orbit and found that the source of the radio emissions changed position with the planet rather than remaining centred on the star.

The frequencies of the bursts also allowed the team to estimate the strength of the planet’s magnetic field. The researchers calculated a lower limit of approximately 1.25 kilogauss, or 1,250 gauss. That is hundreds of times stronger than the magnetic field measured at Jupiter’s surface.

Planetary magnetic fields are scientifically important because they reveal information about conditions deep inside a planet. They are generally produced by the movement of electrically conducting material within the interior, meaning their strength can offer clues about a planet’s composition, temperature and rotation.

A magnetic field can also influence whether a planet retains its atmosphere. It can deflect charged particles carried by stellar winds, although the relationship between magnetism, atmospheric protection and habitability is more complicated than simply having a stronger field.

Beta Pictoris b is not considered a likely home for life. It is a hot, massive gas giant without a known solid surface. However, the detection demonstrates that radio astronomy can reveal properties of exoplanets that are difficult to measure using visible or infrared light.

The finding remains preliminary because the study was released as a preprint and has not yet completed peer review. Independent observations will be needed to confirm both the source and interpretation of the emissions.

If confirmed, the technique could eventually be used to search for magnetic fields around smaller and older planets. More sensitive observatories, including the Square Kilometre Array, may allow astronomers to build the first magnetic survey of distant worlds and determine how planetary magnetism changes with age, mass and environment.