Artist’s concept of TIC365102760 b, nicknamed Phoenix for its ability to survive a red giant star’s intense radiation from up close. Credit: Roberto Molar Candanosa/Johns Hopkins Universitydefying usual degradation by its nearby red giant, retains a thick atmosphere, upending assumptions about atmospheric loss and planetary decay in harsh stellar environments.
The new planet belongs to a category of rare worlds called “hot Neptunes” because they share many similarities with the solar system’s outermost, frozen giant despite being far closer to their host stars and far hotter. Officially named TIC365102760 b, the latest puffy planet is surprisingly smaller, older, and hotter than scientists thought possible. It is 6.2 times bigger than Earth, completes an orbit around its parent star every 4.
“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,” Grunblatt said. “That’s why it 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 be losing their atmospheres in much less extreme environments.”’s Transiting Exoplanet Survey Satellite.
“We don’t understand the late-stage evolution of planetary systems very well,” Grunblatt said. “This is telling us that maybe Earth’s atmosphere won’t evolve exactly how we thought it would.”Puffy planets are often composed of gases, ice, or other lighter materials that make them overall less dense than any planet in the solar system. They are so rare that scientists believe only about 1% of stars have them.