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\t\t\t\t\t\t02\/07\/2025<\/span> Astronomers using the European Space Agency\u2019s Cheops\u00a0mission have caught an exoplanet that seems to be triggering flares of radiation from the star it orbits. These tremendous explosions are blasting away the planet\u2019s wispy atmosphere, causing it to shrink every year.<\/p>\n This is the first-ever evidence for a \u2018planet with a death wish\u2019. Though it was theorised to be possible since the nineties, the flares seen in this research are around 100 times more energetic than expected.<\/p>\n<\/div>\n Thanks to telescopes like the NASA\/ESA\/CSA\u00a0James Webb Space Telescope\u00a0and NASA\u2019s Transiting Exoplanet Survey Satellite (TESS), we already had some clues about this planet and the star it orbits.<\/p>\n The star, named HIP 67522, was known to be just slightly larger and cooler than our own host star, the Sun. But whilst the Sun is a middle-aged 4.5-billion-year-old, HIP 67522 is a fresh-faced 17-million-year-old. It bears two planets. The closer of the two \u2013 given the catchy name HIP 67522 b \u2013 takes just seven days to whip around its host star.<\/p>\n Because of its youth and size, scientists suspected that star HIP 67522 would churn and spin with lots of energy. This churning and spinning would turn the star into a powerful magnet.<\/p>\n Our much-older Sun has its own smaller and more peaceful magnetic field. From studying the Sun, we already knew that flares of energy can burst from magnetic stars when \u2018twisted\u2019 magnetic field lines are suddenly released. This energy can take the form of anything from gentle radio waves to visible light to aggressive gamma rays.<\/p>\n Ever since the first exoplanet was discovered in the 1990s, astronomers have pondered whether some of them might be orbiting close enough to disturb their host stars\u2019 magnetic fields. If so, they could be triggering flares.<\/p>\n A team led by Ekaterina Ilin at the Netherlands Institute for Radio Astronomy (ASTRON) figured that with our current space telescopes, it was time to investigate this question further.<\/p>\n \u201cWe hadn\u2019t seen any systems like HIP 67522 before; when the planet was found it was the youngest planet known to be orbiting its host star in less than 10 days,\u201d says Ekaterina.<\/p>\n The team was using TESS to do a broad sweep of stars that might be flaring because of an interaction with their planets. When TESS turned its eyes to HIP 67522, the team thought they could be on to something. To be sure, they called upon ESA\u2019s sensitive CHaracterising ExOPlanet Satellite,\u00a0Cheops.<\/p>\n<\/p><\/div>\n \u201cWe quickly requested observing time with Cheops, which can target individual stars on demand, ultra precisely,\u201d says Ekaterina. \u201cWith Cheops we saw more flares, taking the total count to 15, almost all coming in our direction as the planet transited in front of the star as seen from Earth.\u201d<\/p>\n Because we are seeing the flares as the planet passes in front of the star, it is very likely that they are being triggered by the planet.<\/p>\n A flaring star is nothing new. Our own Sun regularly releases bursts of energy, which we experience on Earth as \u2018space weather\u2019 that causes the auroras and can damage technology. But we\u2019ve only ever seen this energy exchange as a one-way street from star to planet.<\/p>\n Knowing that HIP 67522 b orbits extremely close to its host star, and assuming that the star\u2019s magnetic field is strong, Ekaterina\u2019s team deduced that the clingy HIP 67522 b sits close enough to exert its own magnetic influence on its host star.<\/p>\n They think that the planet gathers energy as it orbits, then redirects that energy as waves along the star\u2019s magnetic field lines, as if whipping a rope. When the wave meets the end of the magnetic field line at the star\u2019s surface, it triggers a massive flare.<\/p>\n It\u2019s the first time we see a planet influencing its host star, overturning our previous assumption that stars behave independently.<\/p>\n And not only is HIP 67522 b triggering flares, but it is also triggering them in its own direction. As a result, the planet experiences six times more radiation than it otherwise would.<\/p>\n<\/p><\/div>\n Unsurprisingly, being bombarded with so much high-energy radiation does not bode well for HIP 67522 b. The planet is similar in size to Jupiter but has the density of candy floss, making it one of the wispiest exoplanets ever found.<\/p>\n Over time, the radiation is eroding away the planet\u2019s feathery atmosphere, meaning it is losing mass much faster than expected. In the next 100 million years, it could go from an almost Jupiter-sized planet to a much smaller Neptune-sized planet.<\/p>\n \u201cThe planet seems to be triggering particularly energetic flares,\u201d points out Ekaterina. \u201cThe waves it sends along the star\u2019s magnetic field lines kick off flares at specific moments. But the energy of the flares is much higher than the energy of the waves. We think that the waves are setting off explosions that are waiting to happen.\u201d<\/p>\n<\/p><\/div>\n When HIP 67522 was found, it was the youngest known planet orbiting so close to its host star. Since then, astronomers have spotted a couple of similar systems and there are probably dozens more in the nearby Universe. Ekaterina and her team are keen to take a closer look at these unique systems with TESS, Cheops and other exoplanet missions.<\/p>\n \u201cI have a million questions because this is a completely new phenomenon, so the details are still not clear,\u201d she says.<\/p>\n \u201cThere 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 \u2013 for example ultraviolet and X-rays are especially bad news for the exoplanet.<\/p>\n<\/p><\/div>\n \u201cThe second is to find and study other similar star-planet systems; by moving from a single case to a group of 10\u2013100 systems, theoretical astronomers will have something to work with.\u201d<\/p>\n Maximillian G\u00fcnther, Cheops project scientist at ESA, is excited to see the mission contributing to research in a way that he never thought possible: \u201cCheops was designed to characterise the sizes and atmospheres of exoplanets, not to look for flares. It\u2019s really beautiful to see the mission contributing to this and other results that go so far beyond what it was envisioned to do.\u201d<\/p>\n Looking further ahead, ESA\u2019s future exoplanet hunter\u00a0Plato\u00a0will also study Sun-like stars like HIP 67522. Plato will be able to capture much smaller flares to really give us the detail that we need to better understand what is going on.<\/p>\n<\/p><\/div>\n NOTES FOR EDITORS<\/b><\/p>\n \u2018Close-in planet induces flares on its host star\u2019<\/i> by Ekaterina Ilin et al. is published today in Nature. DOI 10.1038\/s41586-025-09236-z<\/p>\n The research was carried out through Cheops\u2019s \u2018Guest Observers\u2019 Programme\u2019. Researchers from outside the Cheops science team are granted time based on an open application process, showcasing the mission\u2019s utility for the scientific community across Europe and worldwide.<\/p>\n In an accompanying paper, published today in Astronomy & Astrophysics (DOI 10.1051\/0004-6361\/202554684), the authors confirm that HIP 67522 is a magnetically active star with strong radio wave emission powered by its magnetic field. The team observed the star at low radio frequencies for about 135 hours with the Australian Telescope Compact Array (ATCA), revealing it as a bright and bursty source of radio waves. At the same time, the authors found no signs of radio wave flares that could be attributed to the interaction of the star with the planet. The non-detection is compatible with expectations that the planet-induced flares are too faint to be detected by ATCA, in line with the Nature paper’s conclusion of magnetic star-planet interaction driving flaring activity.<\/p>\n<\/p><\/div>\n
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\n\t\t\t\t\t\t\t\t\t\t0<\/span> likes<\/small><\/span><\/p>\n<\/header>\nThis planet’s star makes our Sun look sleepy<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nA la carte research with Cheops<\/h3>\n
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\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n<\/p><\/div>\nA self-imposed downfall<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nMore questions than answers<\/h2>\n
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