![\"In](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/astro\/exo-explore\/exoplanet-artists-concepts\/flaring%20star%2021280.png?w=1280&h=1697&fit=clip&crop=faces%2Cfocalpoint\")
<\/a><\/figure>The Discovery<\/h2>\n
A giant planet some 400 light-years away, HIP 67522 b, orbits its parent star so tightly that it appears to cause frequent flares from the star\u2019s surface, heating and inflating the planet\u2019s atmosphere.<\/p>\n
Key Facts<\/h2>\n
On planet Earth, \u201cspace weather\u201d caused by solar flares might disrupt radio communications, or even damage satellites. But Earth\u2019s atmosphere protects us from truly harmful effects, and we orbit the Sun at a respectable distance, out of reach of the flares themselves.<\/p>\n
Not so for planet HIP 67522 b. A gas giant in a young star system \u2013 just 17 million years old \u2013 the planet takes only seven days to complete one orbit around its star. A \u201cyear,\u201d in other words, lasts barely as long as a week on Earth. That places the planet perilously close to the star. Worse, the star is of a type known to flare \u2013 especially in their youth.<\/p>\n
In this case, the proximity of the planet appears to result in fairly frequent flaring.<\/p>\n
Details<\/h2>\n
The star and the planet form a powerful but likely a destructive bond. In a manner not yet fully understood, the planet hooks into the star\u2019s magnetic field, triggering flares on the star\u2019s surface; the flares whiplash energy back to the planet. Combined with other high-energy radiation from the star, the flare-induced heating appears to have increased the already steep inflation of the planet\u2019s atmosphere, giving HIP 67522 b a diameter comparable to our own planet Jupiter despite having just 5% of Jupiter\u2019s mass.<\/p>\n
This might well mean that the planet won\u2019t stay in the Jupiter size-range for long. One effect of being continually pummeled with intense radiation could be a loss of atmosphere over time. In another 100 million years, that could shrink the planet to the status of a \u201chot Neptune,\u201d or, with a more radical loss of atmosphere, even a \u201csub-Neptune,\u201d a planet type smaller than Neptune that is common in our galaxy but lacking in our solar system.<\/p>\n
Fun Facts<\/h2>\n
Four hundred light-years is much too far away to capture images of stellar flares striking orbiting planets. So how did a science team led by Netherlands astronomer Ekaterina Ilin discover this was happening? They used space-borne telescopes, NASA\u2019s TESS<\/a> (Transiting Exoplanet Survey Satellite) and the European Space Agency\u2019s CHEOPS (CHaracterising ExoPlanets Telescope), to track flares on the star, and also to trace the path of the planet\u2019s orbit.<\/p>\n Both telescopes use the \u201ctransit\u201d method to determine the diameter of a planet and the time it takes to orbit its star. The transit is a kind of mini-eclipse. As the planet crosses the star\u2019s face, it causes a tiny dip in starlight reaching the telescope. But the same observation method also picks up sudden stabs of brightness from the star \u2013 the stellar flares. Combining these observations over five years\u2019 time and applying rigorous statistical analysis, the science team revealed that the planet is zapped with six times more flares than it would be without that magnetic connection. \u00a0\u00a0<\/p>\n A team of scientists from the Netherlands, Germany, Sweden, and Switzerland, led by Ekaterina Ilin of the Netherlands Institute for Radio Astronomy, published their paper on the planet-star connection, \u201cClose-in planet induces flares on its host star,\u201d in the journal Nature on July 2, 2025.<\/p>\nThe Discoverers<\/h2>\n
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