TRAPPIST-1e Methane Signal Likely False, Webb Data Suggests Airless Planet

In the TRAPPIST-1 system, which is about 39 light-years away, there are seven planets that are similar in size to Earth, all orbiting a cool red dwarf star. Three of these planets are in the "habitable zone," meaning there's a chance liquid water could be present there if they hold onto their atmospheres. However, recent data from NASA's James Webb Space Telescope suggested there might be methane on TRAPPIST-1e, but scientists now believe those signals were likely just background interference.

The Planetary System

According to NASA, TRAPPIST-1 is a cool red dwarf about 39 light-years away that hosts seven Earth-sized planets. The entire system is compact: all seven planets would fit inside Mercury's orbit, and each orbits the star in just a few Earth days. Three of the planets (d, e, and f) lie in or near the habitable zone, where water might persist – if those worlds have atmospheres. However, TRAPPIST-1 frequently flares, showering its planets with ultraviolet radiation that can strip away atmospheres. This raises doubts about whether these planets can hold onto the air needed for life.

Habitability

TRAPPIST-1d's atmosphere does not appear to contain any carbon dioxide, methane, or water vapour, according to NASA's Webb telescope. This could indicate a very thin atmosphere or none at all. Scientists estimate that the ultraviolet light from TRAPPIST-1e would shred any methane in about 200,000 years, which is far too short for consistent replenishment. All of these results point to TRAPPIST-1e being potentially airless. A habitable-zone planet cannot hold onto surface water, which is essential to life, without an atmosphere.