MeerKAT pins repeating radio bursts to the giant planet Beta Pictoris b
The team used distant quasars as fixed reference points to separate the planet's signal from its star's, then read a magnetic field of at least 1,250 gauss off the emission. The preprint has not been peer reviewed.
The Scientist · Science desk
What happened
- A team led by Kevin Ortiz Ceballos at the Center for Astrophysics, Harvard and Smithsonian, used South Africa's MeerKAT array to pick up faint, repeating radio bursts from the Beta Pictoris system.
- Beta Pictoris b is a gas giant 64 light-years from Earth with a mass roughly ten times Jupiter's, according to NASA.
- The paper was submitted to arXiv on September 15 and has not yet been through peer review.
Why it matters
- What's now possible capability Interior models of giant planets have had solar system fields and theory to work with; a measured field for a young ten-Jupiter-mass object gives them an external number to be tested against.
- What it limits constraint The technique landed on the easiest available target, a young massive planet with an exceptionally strong field, so the smaller worlds where magnetic shielding decides whether an atmosphere survives are still out of reach at this sensitivity.
- What doesn't add up contradiction The authors report a first direct detection of auroral radio emission, while Callingham, who was not involved, will go no further than probably auroral until someone sees the emission pulse with the planet's spin.
- What it sets up precedent Radio technosignature searches now have a documented natural planetary emitter to exclude, plus two concrete tests that did the excluding here: astrometric localization against fixed quasars, and circular polarization.
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Localizing the source has been the hurdle for this kind of work. Earlier radio detections from exoplanetary systems could not be traced to the planet rather than the star [5]. The group handled it with astrometry. They compared their MeerKAT images against the precise positions of extremely distant background quasars, which act as fixed markers, and used them to plot where the star and the planet should sit. The radio signal lined up with Beta Pictoris b [6]. "We can rule out the star, and ... we can say that it's from this one particular planet," Yvette Cendes of the University of Oregon, a member of the team, said [7].
The second line of evidence is polarization. Auroral radio emission is circularly polarized, meaning the orientation of the waves rotates in a circle, and that is what the researchers saw from Beta Pictoris b [12]. The emission comes from charged particles circling in the planet's magnetic field and exciting molecules in its atmosphere [13].
From those measurements the team derived a field of at least 1,250 gauss at the region where the radio waves are produced [9]. Earth's field is about 0.5 gauss and Jupiter's about 4.3 [16], which puts the planet's value at roughly 290 times Jupiter's [29] and about 2,500 times Earth's [30]. "This constitutes the first direct measurement of magnetic field strength for an exoplanet," the authors wrote [8].
The figure is a lower bound at one location, not a global surface field [9]. It is also close to what theory expected: the authors say it matches predictions for the fields generated by young, massive giant planets [18], and at ten Jupiter masses this object sits near the brown dwarf regime, where observed auroras already imply fields of thousands of gauss [19]. "It's an incredibly, incredibly strong magnetic field, much stronger than anything in our solar system," Cendes said [11].
Joe Callingham of the University of Amsterdam, who was not involved, told Science News that clinching the aurora interpretation would take seeing the radio waves pulsate in time, since the aurora should rotate in and out of view as the planet spins, roughly once every eight hours [31]. "So TBD, but, compelling," he said. "It's probably auroral" [32].
The SETI question is the one readers reach for first, and the team knows it. "When people see 'radio signal from an exoplanet,' they think aliens," Cendes said [20]. Live Science notes that technosignatures are a key focus of the search for extraterrestrial intelligence, and that radio signals can be emitted by natural sources too [15]. Suzanne Aigrain, an astrophysics professor at Oxford who was not involved in the study [14], named two: "There are two natural processes that can produce radio emission in exoplanets," she said, listing magnetic reconnection between a close-orbiting planet's field and its star's, and aurorae driven by stellar particles hitting the upper atmosphere [23]. She said the second is what the authors believe they detected [24], and added: "this is definitely not aliens!" [17].
What the measurement is actually for is interior physics. Aigrain said magnetic field measurements matter because how magnetospheres are generated, and what sets their strength, is not fully understood [27]. A field also shields an atmosphere: "On Earth, for example, the magnetic field has played a key role in retaining the atmosphere and shielding life on the planet from harmful high-energy radiation," she said [25]. "The planet in this paper is quite massive and has a thick atmosphere, so even without a strong magnetic field it could probably hold on to its atmosphere, and it is not expected to host life," she said [26].
What to watch
- Peer review of the arXiv preprint, and whether the at-least-1,250-gauss lower bound survives into a published version.
- The Square Kilometre Array, for which MeerKAT is a pathfinder, is expected online in the next few years; Aigrain says it will be significantly more powerful and open up many more systems.
- An independent detection of the same bursts, localized to the planet by another array.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence60
- Adoption
- Not scored
- Hype gap+15
- Incentives25
- Confidence62
Perspective Coverage
5 publishers- Builder
- Builder 58%
- Operator
- Operator 27%
- Investor
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Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
For the first time, astronomers have detected radio signals coming directly from a planet outside our solar system, according to a new preprint study.
- [2]
Suzanne Aigrain said: "Astronomers have been looking for radio signals from exoplanets for some time. There have been tentative, indirect detections before, but this is the first truly convincing direct detection, and it hopefully paves the way for many more."
- [3]
The team wrote in the study, which has not been peer-reviewed yet: "No radio detection has previously been unambiguously localized to an extrasolar planet rather than its host star."
- [4]
Beta Pictoris b is a massive gas giant 64 light-years from Earth with a mass roughly 10 times that of Jupiter, according to NASA.
- [5]
Previous radio detections from exoplanetary systems could not be traced directly to the planet itself because astronomers could not tell whether the signal came from the star or the planet.
- [6]
The researchers compared their radio images with the precise positions of extremely distant background quasars, which acted as fixed markers, to plot the exact positions of the star and the planet; the radio signal lined up with the position of Beta Pictoris b rather than its parent star.
- [7]
Yvette Cendes of the University of Oregon in Eugene said: "We can rule out the star, and ... we can say that it's from this one particular planet."
- [8]
The authors wrote: "This constitutes the first direct measurement of magnetic field strength for an exoplanet."
- [9]
The researchers calculated that Beta Pictoris b has a magnetic field strength of at least 1,250 gauss where the radio waves are produced.
- [10]
A team led by Kevin Ortiz Ceballos at the Center for Astrophysics, Harvard and Smithsonian, used South Africa's MeerKAT radio telescope to study the Beta Pictoris planetary system and picked up faint, repeating bursts of radio signals from it.
- [11]
Cendes said: "It's an incredibly, incredibly strong magnetic field, much stronger than anything in our solar system."
- [12]
Auroras emit radio waves that are circularly polarized, meaning the orientation of the waves rotates in a circle, and that is what the researchers saw from Beta Pictoris b.
- [13]
Auroras are caused by electrically charged particles circling in a planet's magnetic field, exciting molecules in the atmosphere that generate the glow; as the charged particles circle, they emit radio waves.
- [14]
Suzanne Aigrain is a professor of astrophysics at the University of Oxford and was not involved in the study.
- [15]
Artificial radio signals are a key focus in the search for extraterrestrial intelligence, and such technosignatures could suggest advanced technologies built by intelligent extraterrestrial civilizations; however, radio signals can be emitted by natural sources too.
- [16]
Jupiter's magnetic-field strength is about 4.3 gauss and Earth's is about 0.5 gauss, according to Space.com.
- [17]
Aigrain emphasized that "this is definitely not aliens!"
- [18]
The authors state that their result matches theoretical predictions for the strength of the magnetic fields generated by young, massive giant planets.
- [19]
Beta Pictoris b's mass of 10 times Jupiter's puts it close in size to brown dwarfs; scientists have previously seen auroras on brown dwarfs indicating magnetic fields of thousands of gauss, so such a strong field on a large planet is not unexpected.
- [20]
Cendes said: "When people see 'radio signal from an exoplanet,' they think aliens."
- [21]
The paper was submitted September 15 to arXiv.org.
- [22]
Joe Callingham of the University of Amsterdam, who was not involved with the research, said: "This result, if it holds up in peer review, is an incredibly exciting advancement."
- [23]
Aigrain said: "There are two natural processes that can produce radio emission in exoplanets. One is magnetic reconnection, when the planet orbits really close to the star and its magnetic field interacts directly with that of the star. The other is aurorae (like those we have on Earth and on other solar system planets like Saturn, but much stronger), when energetic charged particles streaming from the star interact with the upper atmosphere of the planet."
- [24]
Aigrain added that the aurorae effect "is what the authors of the paper believe they have detected."
- [25]
Aigrain said: "[A] planet's magnetic field shields its atmosphere from the 'wind' of charged particles from [its] star, which might otherwise carry material away from the atmosphere. On Earth, for example, the magnetic field has played a key role in retaining the atmosphere and shielding life on the planet from harmful high-energy radiation."
- [26]
Aigrain said: "The planet in this paper is quite massive and has a thick atmosphere, so even without a strong magnetic field it could probably hold on to its atmosphere, and it is not expected to host life. But in the future we might be able to make similar measurements for smaller planets, for which this shielding effect would be more important."
- [27]
Aigrain said magnetic-field measurements like these are important because we do not fully understand how planets' magnetospheres are generated and what controls how strong they are.
- [28]
The discovery gives scientists a new way to directly measure an exoplanet's magnetic field and test theoretical models of planetary interiors.
- [29]
The 1,250 gauss figure is roughly 290 times Jupiter's magnetic-field strength.
- [30]
The 1,250 gauss figure is about 2,500 times Earth's magnetic-field strength.
- [31]
Callingham says that to really clinch the case for an aurora on an exoplanet you would want to see the radio waves pulsate in time, because the aurora should rotate in and out of view as the planet spins, roughly once every eight hours for Beta Pictoris b.
- [32]
Callingham said: "So TBD, but, compelling. It's probably auroral."
- [33]
MeerKAT is a pathfinder instrument for the Square Kilometre Array, expected to come online in the next few years; Aigrain said that observatory "will be significantly more powerful, so there will be many more systems where we can look for this type of signal."
Sources
5 independent publishers whose own reporting we read for this story.
- discovermagazine.comRadio Emission Detected from Massive Exoplanet Reveals a Magnetic Field Far Stronger Than Earth's
1 article · October 2, 2026
- livescience.comAstronomers detected radio signals coming from an exoplanet for the first time. Spoiler alert: It's not aliens.
1 article · September 23, 2026
- mezha.netАстрономи зафіксували радіосигнал від екзопланети Бета Живописця b
1 article · October 2, 2026
- phys.orgAstronomers detect radio signals coming from an exoplanet for the first time
1 article · September 22, 2026
- sciencenews.orgFirst radio waves seen from an exoplanet hint at otherworldly auroras
1 article · September 21, 2026
Topics and entities
Topics
- Planetary magnetic fields
- Radio Astronomy
- Exoplanet radio emission