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SKA Detects Magnetic Fields on Distant Exoplanet
Confirmed
In Short: Beta Pictoris b, a gas giant, has become the first exoplanet confirmed to emit auroral radio waves and have its magnetic field directly measured.
Beta Pictoris b, a gas giant roughly 12 times Jupiter's mass orbiting a young star about 64 light-years from Earth, has become the first exoplanet confirmed to emit auroral radio waves and have its magnetic field directly measured.
The MeerKAT team detected bursts reaching 3.5 GHz, confirming a minimum magnetic field of 1,250 gauss at the emission site.
This rapid spin, combined with a kilogauss-scale magnetic field, drives a phenomenon called magnetosphere-ionosphere coupling, generating large electrical currents that cascade electrons downward along field lines into the aurora.
The 8-hour gap between the first and third radio bursts detected in the L-band session is consistent with the planet's rotation period, suggesting the rotationally modulated aurora bursts are spinning in and out of the line of sight as the planet turns.
The magnetic field of Beta Pictoris b registers at least 1,250 gauss at the emission site, making it roughly 2,500 times stronger than Earth's surface magnetic field.
When energetic electrons spiral through a strong magnetosphere, they emit coherent radio waves at a frequency directly proportional to the local magnetic field strength.
The highest-frequency radio waves a planet can emit are set by its peak magnetic field strength, providing a direct read-out of field strength without the need for models or assumptions about interior structure.
The SKA could potentially revolutionize the search for magnetic fields on exoplanets by building off decades-long research into ultracool dwarfs (UCDs).
The auroral signal reveals a magnetic field thousands of times stronger than Earth’s, and the phenomenon is called the electron cyclotron maser instability (ECMI), where energetic electrons moving through a magnetic field generate intense radio waves.
This study, posted September 15 as an arXiv preprint and not yet peer reviewed, marks both the first radio emission securely localized to an exoplanet and the first direct measurement of an exoplanet’s magnetic-field strength.
What this adds
The research adds to the understanding of exoplanet magnetic fields, which could be crucial for identifying Earth-like worlds capable of supporting life.
What's confirmed
- Beta Pictoris b, a gas giant roughly 12 times Jupiter's mass orbiting a young star about 64 light-years from Earth, has become the first exoplanet confirmed to emit auroral radio waves and have its magnetic field directly measured.
- The MeerKAT team detected bursts reaching 3.5 GHz, confirming a minimum magnetic field of 1,250 gauss at the emission site.
- This rapid spin, combined with a kilogauss-scale magnetic field, drives a phenomenon called magnetosphere-ionosphere coupling, generating large electrical currents that cascade electrons downward along field lines into the aurora.
- The 8-hour gap between the first and third radio bursts detected in the L-band session is consistent with the planet's rotation period, suggesting the rotationally modulated aurora bursts are spinning in and out of the line of sight as the planet turns.
- The magnetic field of Beta Pictoris b registers at least 1,250 gauss at the emission site, making it roughly 2,500 times stronger than Earth's surface magnetic field.
- When energetic electrons spiral through a strong magnetosphere, they emit coherent radio waves at a frequency directly proportional to the local magnetic field strength.
- The highest-frequency radio waves a planet can emit are set by its peak magnetic field strength, providing a direct read-out of field strength without the need for models or assumptions about interior structure.
- The SKA could potentially revolutionize the search for magnetic fields on exoplanets by building off decades-long research into ultracool dwarfs (UCDs).
- The auroral signal reveals a magnetic field thousands of times stronger than Earth’s, and the phenomenon is called the electron cyclotron maser instability (ECMI), where energetic electrons moving through a magnetic field generate intense radio waves.
- This study, posted September 15 as an arXiv preprint and not yet peer reviewed, marks both the first radio emission securely localized to an exoplanet and the first direct measurement of an exoplanet’s magnetic-field strength.
What's still developing
- Now, an international team of scientists might help shed new light on studying exoplanet magnetic fields, as they discussed in a chapter published in Advancing Astrophysics with the SKA II, which is a 2026 science book sponsored by the Square Kilometre Array Observatory (SKAO).
- However, this study discusses how UCDs could be prime targets since astronomers have been detecting radio waves from them for several decades.
- As noted, detecting exoplanet magnetic fields is still in the very early stages of research, with astronomers very recently announcing the discovery of radio signals emanating from an exoplanet, Beta Pictoris b.
- Also, a June 2026 study published in Nature Astronomy discussed the detection of a magnetic field around a hot Jupiter exoplanet.
- Studying exoplanets has provided astronomers with a plethora of insights regarding what characteristics need to be searched to find life beyond Earth.
- However, astronomers have learned that certain stars are more active than our Sun, resulting in exoplanets orbiting in the habitable zone being blasted with far more radiation than Earth could handle.
- In recent years, astronomers have recognized that a planet’s magnetic field, which shields the Earth from harmful radiation, could be a prime characteristic for identifying Earth-like worlds.
- This includes potentially detecting not only auroral radio signals but also using these radio signals to further characterize the exoplanet’s magnetic field, radiation belt, and even potential satellites, with the researchers only using the term “exomoon” once in the paper.
- “It’s an incredibly, incredibly strong magnetic field, much stronger than anything in our solar system,” astronomer Yvette Cendes told Science News.
- The signal appears to come from an aurora — the same broad family of magnetic phenomena that produces Earth’s beautiful northern and southern lights and Jupiter’s powerful radio bursts.
- During the mission's fourth flyby in September 2024, this instrument detected how particles from a solar eruption penetrated Mercury's magnetic field and impacted the surface.
- Said co-author Rami Vainio, the co-Principal Investigator of SIXS and a professor of space physics at the University of Turku: Mercury's magnetic field is weaker than Earth's, and its magnetosphere is much smaller than Earth's.