{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"f99e71388d14ef5eebfc3cf4f0b143fd9483e5dbde659ad34aa85b95d3e7aa40","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["303d116fd23fc42c2764c3536290b7b73d77a519648d35e2a16e8b389926db61","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"83aa60b95cf73af893198d259edb2fb23f273c4e09bfb01b15bfd07465e84cc6","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"astro.biosignatures.k2-18b-dms","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"A team using JWST reported hints of dimethyl sulfide, a gas made on Earth almost only by marine life, on the planet K2-18 b. Other teams analyzing the same data find no reliable signal.","posed_since":"2023","precise":"K2-18 b is a temperate sub-Neptune ($R \\sim 2.6 R_{\\mathrm{earth}}, M \\sim 9 M_{\\mathrm{earth}}$) orbiting an M dwarf, with $\\mathrm{CH_4}$ and $\\mathrm{CO_2}$ detected by JWST in 2023. Determine whether dimethyl sulfide (and dimethyl disulfide) is present at $\\ge 5\\sigma$ in JWST NIRISS, NIRSpec and MIRI spectra, and if present, whether abiotic photochemistry or delivery can produce the inferred abundance.","problem_ref":"303d116fd23fc42c2764c3536290b7b73d77a519648d35e2a16e8b389926db61","references":"","settled_by":"Additional JWST transits analyzed by independent pipelines with agreed systematics treatment, reaching a $5\\sigma$ detection or an upper limit below the claimed abundance.","status_note":"A 2025 MIRI analysis reported about $3\\sigma$ evidence for dimethyl sulfide or dimethyl disulfide; independent 2025 reanalyses found no statistically significant evidence, and 2026 papers model the spectrum without dimethyl sulfide.","title":"Does the atmosphere of K2-18 b contain dimethyl sulfide?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"d2f48b89150bc46d4792f238a3d169ababefcf4f9f5cb1feaf01e9a76640d038","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e76d2a28430b37e3ce6b44347bb9347e2174eeff6a7655d47c9a89a7d7a851a5","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"jwy0pwJ4BwN7GaOwskS0kU1Utcp1egfw5r1MQ5YcFh2YEjy1EfV2dooL745QVNzXU2CEXH5NC-O_yanY-iseDQ"},"schema":"pubphys.envelope/1"},"record_hash":"d2f48b89150bc46d4792f238a3d169ababefcf4f9f5cb1feaf01e9a76640d038","leaf_index":2302}