James Webb Telescope Detects Unusual Carbon Dioxide Levels in Interstellar Comet 3I/ATLAS
NASA's James Webb Space Telescope has observed interstellar comet 3I/ATLAS, revealing an unusually high carbon dioxide to water ratio in its coma, suggesting unique formation conditions.
NASA's James Webb Space Telescope (JWST) has observed interstellar comet 3I/ATLAS, revealing an unusually high carbon dioxide (CO₂) to water (H₂O) ratio in its coma. The Near-Infrared Spectrograph instrument detected a CO₂/H₂O mixing ratio of 8.0 ± 1.0, among the highest recorded in a comet. This suggests that 3I/ATLAS may have formed close to the CO₂ ice line in its parent protoplanetary disk or contains ices exposed to higher radiation levels than typical solar system comets.
Discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS), 3I/ATLAS is the third confirmed interstellar object to pass through our solar system. It is traveling at approximately 130,000 miles per hour and is expected to make its closest approach to the Sun in late October 2025.
The JWST's observations provide valuable insights into the comet's composition and origin, offering a rare opportunity to study material from another star system.