Methanol-Rich Coma of Interstellar Visitor 3I/ATLAS Reveals Distinct Chemistry From Solar System Comets

To the point

3I/ATLAS shows an unusually methanol-rich coma for an interstellar visitor, with methanol to hydrogen cyanide ratios around 70–120 measured by ALMA, suggesting methanol-bearing ices sublime from many grains while HCN mainly comes from the nucleus, a fingerprint Nathan Roth calls from another solar system, and Micah Hanks notes it adds complexity to JWST’s CO2-dominated picture of its chemistry, implying diverse formation histories.