Overview

• James Webb obtained the first detailed infrared spectra of 3I/ATLAS on August 6, with results posted as an arXiv preprint slated for The Astrophysical Journal Letters.
• The coma is dominated by carbon dioxide, with an observed CO2-to-water ratio of roughly 8:1, far higher than in typical Solar System comets.
• Water vapor appears comparatively scarce, suggesting a nucleus structure that limits heat penetration and allows CO2 and CO to escape more readily than H2O.
• Imaging and analysis indicate a pronounced sunward dust enhancement rather than an even dust envelope around the comet.
• Dynamical and compositional clues point to an ancient origin estimated at roughly 3–11 billion years, possibly in the Milky Way’s thick disk, and researchers report no evidence for a non-natural origin.