TRAPPIST-1 d: Searching for Signs of Air on a Nearby Earth-Sized World

Astronomers used JWST to study TRAPPIST-1 d, an Earth-sized planet near the habitable zone of its star. The data revealed a flat transmission spectrum, ruling out thick atmospheres of hydrogen, methane, water vapor, or carbon dioxide. This suggests TRAPPIST-1 d is either airless, has only a very thin atmosphere, or is shrouded by high-altitude clouds, offering key insights into how rocky planets around small stars evolve.