3I/ATLAS: A Methanol-Rich Interstellar Comet as a Fingerprint from a Distant Star System

To the point

3I/ATLAS is an interstellar comet that was discovered on July 1, 2025 and is passing through our solar system, offering a rare glimpse of material from another star, ALMA finds it unusually rich in methanol relative to hydrogen cyanide with methanol coming from both the nucleus and the coma while hydrogen cyanide mostly comes from the core, JWST data showed a CO2‑dominated coma far from the Sun, SPHEREx detected dust, water, organic molecules and CO2 in the coma, Nathan Roth calls these measurements a fingerprint from another solar system, interstellar comets act as frozen time capsules, and as surveys like the Vera Rubin Observatory come online we expect more visitors studied by many missions including Hubble, JWST, Mars rovers and the Juice spacecraft.