TRAPPIST-1 d Update

NASA's JWST finds no Earth-like atmosphere on TRAPPIST-1 d, reshaping expectations for an Earth twin.

TRAPPIST-1 d Lacks Earth-like Atmosphere

The TRAPPIST-1 system contains seven Earth-sized planets orbiting a dim red dwarf. TRAPPIST-1 d sits in the star’s habitable zone, which had scientists hopeful it could retain an atmosphere suitable for liquid water. Using NASA’s James Webb Space Telescope, researchers studied the planet with the Near Infrared Spectrograph, but no signatures of water vapor, methane, or carbon dioxide were detected.

Researchers caution that the absence of those signals does not prove the planet is barren. Explanations include a very thin atmosphere similar to Mars, thick high altitude clouds masking signatures like Venus, or no atmosphere at all. The planet’s proximity to the star and the star’s flares could strip away air over time, while planets farther out in the system might still hold onto atmospheres.

This result nudges back expectations that TRAPPIST-1 d could be a close Earth twin. It also underscores how challenging habitability is around red dwarfs, where intense stellar activity can erode atmospheres even for rocky, Earth-sized worlds. The JWST finding is technically a win for the science of exoplanets because it narrows the field and sharpens questions.

Going forward, scientists may shift focus to the more distant planets in the TRAPPIST-1 system and to new missions like Habitable Worlds Observatory. The work reminds us that habitability is a spectrum not a single yes or no answer. It also calls for clearer communication with the public about what a planet must have to support life.

Highlights

The universe keeps its secrets, but the quest to understand them keeps moving forward.