3I/ATLAS · Interstellar Comet Explorer
June 2026 — JWST detected methane in the coma of 3I/ATLAS, the first chemistry ever measured on a visitor from another star system
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Detected in Coma · JWST June 2026 · click to highlight trail
Detection Pipeline
What Is 3I/ATLAS?
3I/ATLAS is the third confirmed interstellar object (after 1I/'Oumuamua in 2017 and 2I/Borisov in 2019). Its eccentricity of ~4 is far above the threshold of 1.0 for a solar escape orbit, proving it arrived from another star system. It was discovered in late 2025 by the ATLAS sky survey and reached perihelion inside the inner solar system.