A rare exoplanet that should have been “stripped” by the intense radiation of its nearby red giant star is instead gaining an atmosphere, forcing scientists to reevaluate their theories about how planets die in extreme environments.

Named TIC365102760 B and nicknamed the “Phoenix” due to its ability to survive, the newly discovered planet demonstrates the enormous diversity of solar systems and the complexity of planetary evolution.

The planet belongs to the category of “hot Neptunes”, that is, giant exoplanets with many similarities to Uranus or Neptune, the most distant, icy giants of the Solar System, although they are much closer to their host stars and are much hotter . This particular planet is 6.2 times larger than Earth, completes an orbit around its star every 4.2 days, and is about six times closer to its star than Mercury is to the Sun.

The process of stripping its atmosphere must have been at a slower rate than scientists thought. They estimate that the planet is 60 times less dense than the densest “hot Neptune” discovered to date, and that it will not survive more than 100 million years.

Exoplanets like this one aren’t discovered as often because their smaller size makes them harder to spot. The research team used a new method to detect it.

“It’s the smallest planet we’ve ever found around one of these red giants, and probably the lowest-mass planet orbiting a giant star we’ve ever seen,” notes Johns Hopkins University astrophysicist and lead author Sean Granblatt. of research. “That’s why he looks really weird. “We don’t know why it still has an atmosphere, when other ‘hot Neptunes’ that are much smaller and much denser seem to lose their atmospheres in much less extreme environments,” he adds. He says the findings could help scientists better understand how atmospheres like Earth’s might evolve.

The findings are published in The Astronomical Journal.