Astronomers have witnessed a planet causing storms to erupt on its parent star, a discovery that could reshape our understanding of how planets and stars interact and evolve together. These findings are published today in the scientific journal Nature.
Scientists have discovered the first clear case of a planet causing its host star to flare, offering new insights into the dramatic interactions between stars and their closely orbiting planets. The research was led by Dr. Ekaterina Ilin at ASTRON (Netherlands Institute for Radio Astronomy), along with an international team of collaborators.
Published by the editorial team, 2 July 2025
HIP 67522: a young and dynamic star system
The study focused on HIP 67522, a young star system 408 light-years away in the Upper Centaurus Lupus region. At just 17 million years old, a mere infant in cosmic terms, this system contains a giant planet in an extremely tight orbit, completing a lap around its star every 6.95 days. “We’ve found the first clear evidence of magnetic star-planet interaction, where a planet triggers energetic flares on its host star,” said Ekaterina Ilin. “What’s particularly exciting is that this interaction has persisted for at least three years, allowing us to study it in detail.”
TESS and CHEOPS reveal magnetic disturbances
By analyzing five years of data from NASA’s TESS satellite and the European Space Agency’s CHEOPS telescope, the researchers discovered that flares on HIP 67522 are predominantly observed when the planet passes in front of the star from our perspective on Earth. This observation allowed them to show that the flares occur when the planet disturbs the star’s magnetic field lines, sending energy back to the star’s surface along these magnetic highways, where it triggers explosive releases of energy.
Flares six times more frequent
The findings also show that the planet is exposed to its host star’s flares approximately six times more often than it would have without the interaction. The enhanced flaring has significant implications for the planet itself, which recent observations with the James Webb Space Telescope revealed to have an unusually expanded atmosphere. “The planet is essentially subjecting itself to an intense bombardment of radiation and particles from these induced flares,” explained Harish K. Vedantham, co-author and researcher at ASTRON. “This self-inflicted space weather likely causes the planet’s atmosphere to puff up and may dramatically accelerate the rate at which the planet is losing its atmosphere.”
In an accompanying paper, published in Astronomy & Astrophysics, the authors confirmed that HIP 67522 is a magnetically active star with strong radio emission powered by its magnetic field. The team observed the star-planet system at low radio frequencies for about 135 hours with the Australian Telescope Compact Array, revealing it as a bright and bursty source or emission. At the same time, the star showed no signs of radio emission that could be attributed to the interaction with the planet. The non-detection is compatible with expectations, supporting the main paper’s conclusion of magnetic star-planet interaction driving flaring activity.
A blueprint for studying planetary evolution
This discovery establishes HIP 67522 as an archetypal system for studying how magnetic interactions between stars and planets can affect planetary evolution, particularly for young planets. The team plans further observations of this and other systems to better understand how energy is transported and released along the planet-star connection, how common this phenomenon is among young planetary systems and what it means for the ability of young planets to retain their nascent atmospheres.
