High Methanol Abundance in Interstellar Comet 3I/ATLAS

Astronomers have uncovered an unexpected abundance of methanol in the interstellar comet 3I/ATLAS, offering a rare glimpse into the chemical makeup of a distant star system. Detected in July 2025 by the ATLAS survey telescope in Chile, the comet became only the third confirmed interstellar object to pass through our solar system, hurtling past the sun at its closest point in the fall of that year before swinging by Earth and continuing outward.

Researchers, using the Atacama Large Millimeter/submillimeter Array in Chile's Atacama Desert, observed the comet between August and October 2025, just before its perihelion. The telescope captured emissions from the comet's coma, the hazy envelope of gas and dust surrounding its nucleus. Analysis revealed that 3I/ATLAS contains unusually high levels of methanol, a simple organic molecule also known as wood alcohol, with ratios to hydrogen cyanide reaching as high as 120 to 1. This makes it one of the most methanol-rich comets ever studied, surpassing nearly all known examples from our own solar system by up to four times.

"Observing 3I/ATLAS is like taking a fingerprint from another solar system," said Nathan Roth, an assistant professor...