In the cosmic ballet of the past decade, astronomers have uncovered a dizzying number of exoplanets whirling around their stars in orbits shorter than 10 days. These are not your average planetary paths.
Unlike the well-spaced orbits of our solar system, these exoplanets skim so close to their stars that they stir the very fabric of stellar magnetism like dancers brushing too near the orchestra pit and rattling the instruments.
This intimate proximity has long hinted at a tantalizing possibility that planets might not just orbit their stars but agitate them, twisting magnetic field lines, igniting flares, and amplifying emissions from the star’s surface and atmosphere. Yet, despite years of searching, the evidence for such magnetic star-planet interactions has remained elusive… until now.
Enter HIP 67522, a youthful, 17-million-year-old G-type star, already known to host two tightly orbiting planets. Thanks to the sharp eyes of the European Space Agency’s Cheops mission, astronomers have now caught one of these exoplanets red-handed, triggering colossal flares on its host star. These aren’t just fireworks for show. The planet’s atmosphere is taking a beating, blasted by such intense stellar energy that it’s shrinking year by year.
The star is slightly larger and cooler than our host star, the Sun. However, the sun is a middle-aged 4.5-billion-year-old, and HIP 67522 is a fresh-faced 17-million-year-old.
It hosts two planets named HIP 67522 b and HIP 67522 c. HIP 67522 b is close enough to the star that it takes just seven days to whip around its host star. It is one of the youngest transiting planets of any type.
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For decades, astronomers have whispered about the possibility of a planet so recklessly close to its star that it might be hastening its demise, a “planet with a death wish.” Now, for the first time, that dark prophecy has found a name: HIP 67522b. The planet orbits so near its youthful, volatile star that it’s triggering flares of unimaginable power, 100 times more energetic than scientists ever predicted.
Because HIP 67522 is young and large, the star is expected to be full of energy, spinning fast and churning inside. All that motion acts like a giant dynamo, turning the star into a powerful magnet.
When HIP 67522 b was discovered, it was the youngest known planet orbiting its star in under 10 days. Astronomers were using NASA’s TESS to search for stars flaring due to interactions with nearby planets. When TESS observed HIP 67522, the team suspected a magnetic connection and turned to ESA’s ultra-precise Cheops satellite for confirmation.
Cheops detected 15 flares, most occurring as the planet passed in front of the star. This is strong evidence that the planet was triggering them.
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This is the first time a planet has been seen influencing its star’s behavior, reversing the usual one-way energy flow from star to planet.
HIP 67522 b orbits extremely close to a young, magnetically active star. As it orbits, the planet stirs up energy and sends waves along the star’s magnetic field like snapping a whip. When these waves hit the star’s surface, they explode into powerful flares.
These flares are directed toward the planet itself, bombarding it with six times more radiation than it would otherwise receive. Bombarded by intense, high-energy flares from its host star, the planet’s feathery atmosphere is being stripped away at an alarming rate. Over the next 100 million years, it is predicted to shrink dramatically from a Jupiter-sized giant to something closer in size to Neptune.
HIP 67522 b isn’t just a victim; it’s also the spark. As it orbits, the planet sends waves along the star’s magnetic field lines, like flicking a switch. These waves don’t carry much energy themselves, but they seem to ignite massive flares and explosions that were already primed and waiting to erupt.
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Astronomers have found a couple of similar systems in the universe after the discovery of HIP 67522.
Ekaterina Ilin at the Netherlands Institute for Radio Astronomy (ASTRON) said, “We are keen to take a closer look at these unique systems with TESS, Cheops, and other exoplanet missions.”
“I have a million questions because this is a completely new phenomenon, so the details are still not clear.”
“There are two things that I think are most important to do now. The first is to follow up in different wavelengths (Cheops covers visible to near-infrared wavelengths) to find out what kind of energy is being released in these flares—for example, ultraviolet and X-rays are especially bad news for the exoplanet.”
“The second is to find and study other similar star-planet systems; by moving from a single case to a group of 10–100 systems, theoretical astronomers will have something to work with.”
Journal Reference:
- Ilin, E., Vedantham, H.K., Poppenhäger, K., et al. Close-in planet induces flares on its host star. Nature (2025). DOI: 10.1038/s41586-025-09236-z
