A Carnegie-led team of astronomers detected the strongest evidence yet of an atmosphere around a rocky planet beyond our solar system. Their work, published in The Astrophysical Journal Letters, used NASA’s JWST to reveal an alien atmosphere in an unexpected place—an ancient, ultra-hot super-Earth that likely hosts a magma ocean.
TOI-561 b is a rocky world that’s about twice Earth’s mass but bears little resemblance to our home planet due to its proximity to its host star. Although the star is slightly less massive and cooler than our sun, the planet orbits at one fortieth the distance of Mercury in our own solar system. On TOI-561 b, a year lasts just 10.56 hours, and one side of the planet is in perpetual daylight.
“Based on what we know about other systems, astronomers would have predicted that a planet like this is too small and hot to retain its own atmosphere for long after formation,” explained Carnegie Science Postdoctoral Fellow Nicole Wallack, the paper’s second author. “But our observations suggest it is surrounded by a relatively thick blanket of gas, upending conventional wisdom about ultra-short-period planets.”
