Overview
- The Nature papers published Monday, June 22, report that coordinated JWST NIRSpec, ALMA and VLT observations measured isotopes in 3I/ATLAS’s coma and found a chemical signature unlike any Solar System comet.
- JWST detected extremely high deuterium in the comet’s water, roughly tens of times higher than Solar System comets, a signature that forms when ices condense at temperatures near 30 kelvin.
- Ground spectra show unusually low 13C and anomalous nitrogen ratios consistent with a metal-poor birth environment, and researchers say those isotopes combined with models imply a formation age of about 10 to 12 billion years while noting the age is model dependent.
- Independent searches by NASA and the SETI Institute found no evidence of technology, and orbit measurements confirm 3I/ATLAS is on a hyperbolic path leaving the Solar System and currently beyond the orbit of Saturn.
- This is the first high-fidelity isotopic readout of an interstellar object, giving scientists a direct sample for studying early galactic chemistry and underscoring how JWST, ALMA, VLT and upcoming surveys like the Rubin Observatory will change our view of material exchanged across the Milky Way.