Astronomers have detected variable radio bursts from Beta Pictoris b, a massive gas giant located roughly 63 light-years from Earth. Using South Africa’s MeerKAT radio telescope array, researchers captured the emissions to make what is described as the first direct measurement of an exoplanet’s magnetic field.
Habitability is probably one of the main reasons we’re interested in magnetospheres,
said Yvette Cendes, an astronomer at the University of Oregon and an author of the paper, speaking to the New York Times.
An international team of researchers has captured radio wave emissions originating from beyond our solar system, tracing repeated signals to a planet orbiting the star Beta Pictoris. The discovery marks the first time scientists have detected radio signals coming directly from an exoplanet rather than its host star or an entire stellar system.
The target of the observation, Beta Pictoris b, is a young gas giant discovered in 2008 through direct imaging. Located approximately 63 light-years away, the planet has a mass estimated at roughly 12 times that of Jupiter and orbits its star once every 23.6 years at a distance of about 10.018 AU. The host star itself is roughly 23 million years old and about 1.75 times heavier than our Sun. The planet takes nearly 24 years to complete an orbit that carries it as far as 0.55 arcseconds from its star.
MeerKAT Array Isolates Signals From Beta Pictoris b
Kevin Ortiz Ceballos, a doctoral researcher at the Harvard & Smithsonian Center for Astrophysics, spotted the signal while sorting through survey data alongside his adviser, Edo Berger. The astronomers detected these signals using the MeerKAT array, allowing the team to distinguish short, repeated bursts from the planet’s location.
According to researchers from Harvard and the University of Oregon, these characteristics point directly to massive auroras generated on the exoplanet.
Auroral Emissions Reveal an Extraordinary Magnetic Field
The frequency of the recorded radio waves allowed astronomers to calculate the magnetic field strength at the signal source. To put it in perspective, Earth’s magnetic field stands at about 0.5 gauss, whereas Jupiter attains up to 14 gauss, meaning Beta Pictoris b clearly surpasses both in magnetic field strength.
Researchers attribute this massive intensity to the planet’s young age and rapid rotation. This fast rotation produces strong electrical currents, which lead to the repeated radio emissions.
Implications for Exoplanet Research and Habitability
Planetary magnetic fields play a critical role in shielding atmospheres from stellar winds and radiation, making magnetosphere detection a key milestone in the search for potentially habitable worlds. Solar radiation streaming off the sun would otherwise strip away Earth’s atmosphere and ruin surface conditions for life, but the planet’s magnetic field shields against this threat.
The research team has posted their findings online on arXiv while awaiting formal peer review.
Nobody has seen radio emission from a planet in this way,
researchers noted regarding the milestone.