{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"38d5d7173ec2df4be75ca81091ee2b576589665c82b1739efe2e37373a479897","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"3cdbd7e6d1caffc5688d17d0267731096a2d93f00d4d7a6a370e8941a9354290","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"astro.interstellar-objects.composition","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"2I/Borisov carried an unusually large share of carbon monoxide and 3I/ATLAS showed a coma dominated by carbon dioxide. Whether such differences reflect where they formed or billions of years of cosmic-ray exposure in space is unknown.","posed_since":"","precise":"Compare volatile and metal abundance ratios ($\\mathrm{CO}/\\mathrm{H2O}, \\mathrm{CO2}/\\mathrm{H2O}, \\mathrm{Ni}/\\mathrm{Fe}$) of 2I/Borisov and 3I/ATLAS with Solar System comets, and determine whether the differences reflect formation location and stellar environment or processing during Gyr-long interstellar travel. The answer is a classification of composition differences by origin, with predictions testable on future objects.","problem_ref":null,"references":"","settled_by":"Spectroscopic surveys of a sample of interstellar comets compared with laboratory and model predictions of cosmic-ray processing of ices.","status_note":"JWST spectra in 2025 showed a CO2-dominated coma of 3I/ATLAS ($\\mathrm{CO2}/\\mathrm{H2O} \\sim 8$), VLT spectra detected nickel vapor with little or no iron, and its non-gravitational acceleration near perihelion is attributed to outgassing.","title":"Do interstellar comets differ in composition from Solar System comets?","topic_ref":"91b19694864393f36b4b275d23c992a261a21df30ecbe64b28d991279c458961"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5e67d4f52e45b20350abba975abfc3ba829196f2e1b2485f2ba5959692bfdb06","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e2db37225cfcd7132527be1aa87579ae13a29f720561afed993cd3cfbc652495","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"CVkq11WQHxq47BD2GdAIMZ6yoko5dnQCN1dfwMV3gvrwuoRYHSbwTfM_HYje00HdvcPCHWEDKpu7GUWCcoMdBg"},"schema":"pubphys.envelope/1"},"record_hash":"5e67d4f52e45b20350abba975abfc3ba829196f2e1b2485f2ba5959692bfdb06","leaf_index":561}