{"id":223,"date":"2025-07-07T06:58:43","date_gmt":"2025-07-07T13:58:43","guid":{"rendered":"https:\/\/scienceblog.com\/esa\/?p=223"},"modified":"2025-07-07T06:58:43","modified_gmt":"2025-07-07T13:58:43","slug":"planet-forces-its-star-to-attack-it-with-solar-flares","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/esa\/2025\/07\/07\/planet-forces-its-star-to-attack-it-with-solar-flares\/","title":{"rendered":"Planet Forces Its Star to Attack It With Solar Flares"},"content":{"rendered":"

A young planet is literally making its star angry. Astronomers have discovered that HIP 67522 b, a gas giant orbiting dangerously close to its 17-million-year-old host star, triggers magnetic eruptions that bombard the planet with six times more radiation than it would normally receive.<\/p>\n

This cosmic act of self-destruction represents the first confirmed case of a planet inducing stellar flares through magnetic interaction\u2014and it’s slowly destroying the planet’s atmosphere in the process.<\/p>\n

The discovery, published in Nature<\/a>, solves a decades-old mystery about how close-orbiting planets might interact with their stars’ magnetic fields and reveals a dramatic example of planetary suicide by solar weather.<\/p>\n

Magnetic Tug-of-War<\/h2>\n

HIP 67522 b orbits its star every 6.95 days at a distance of just 12 stellar radii\u2014close enough to disturb the star’s magnetic field lines. Think of it like a moon creating tidal forces, except instead of pulling on oceans, the planet tugs on invisible magnetic threads that stretch between the two bodies.<\/p>\n

Using five years of observations from NASA’s TESS satellite and the European CHEOPS telescope, researchers tracked 15 stellar flares and found something remarkable: 11 of them clustered around the planet’s transit phase, when it passes in front of the star as viewed from Earth. The statistical odds of this happening by chance? Less than one in a thousand.<\/p>\n

“The planet orbits less than 12 stellar radii away from the star, probably placing it in the sub-Alfv\u00e9nic regime,” the researchers explain. In this zone, magnetic disturbances can travel along field lines back to the star’s surface, triggering explosive flares at specific “footpoint” locations.<\/p>\n

A Planet’s Death Spiral<\/h2>\n

The consequences for HIP 67522 b are severe. The planet experiences a dramatically elevated flare rate during specific parts of its orbit, creating what astronomers call “self-inflicted space weather.” Key findings include:<\/p>\n