{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8d5f5e61eb28b053153e9128c08af8581bc8c09817c9ac625fe94197ad72686d","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"f330586d728f579e1a4cdf7df08fae7c481ac8ae2d6085c66970d7402ddfc3f3","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":"1","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 CH4 and CO2 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":null,"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":"59b283291ab553a122fd70aabfbd2c1ce03ef623f8bb56636d5ec28be91c14ab"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"303d116fd23fc42c2764c3536290b7b73d77a519648d35e2a16e8b389926db61","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"0340014f5ccb9e5257be927d5408ee326ef50b3edbd7535fe02721e71df9ec66","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"SjSDIbpV50NMly7W5fUU04aiwZzJVA0rUcWwTBcOZXuB-ofJvvGLaPxuOtGT6upCdWVgKNXc5BfrjdH4UfuvDA"},"schema":"pubphys.envelope/1"},"record_hash":"303d116fd23fc42c2764c3536290b7b73d77a519648d35e2a16e8b389926db61","leaf_index":487}