Overview

• The team led by Caroline Piaulet-Ghorayeb observed two transits of TRAPPIST-1d with JWST’s NIRSpec and detected no absorption lines for key molecules including H₂O, CO₂, CO, CH₄ and SO₂.
• Researchers state that TRAPPIST-1d should be removed from the current roster of potential Earth analogs but emphasize that ultrathin atmospheres or high-altitude clouds could still hide from transit spectroscopy.
• Intense flares and stellar winds from the active red dwarf TRAPPIST-1 are plausible drivers of atmospheric loss on its close-in planets like TRAPPIST-1d.
• Ongoing JWST observations of the more distant TRAPPIST-1e, f and g aim to probe their atmospheres despite the weaker spectral signals caused by lower temperatures and larger orbital distances.
• The findings were published in The Astrophysical Journal (doi: 10.3847/1538-4357/adf207) and publicized by the Space Telescope Science Institute, illustrating both the capabilities and limits of NIRSpec.