{"slug":"exoplanets-biosignatures","topic":"exoplanets-biosignatures","title":"Exoplanets & Biosignatures: State of the Field (October 2026)","summary":"This dossier maps exoplanet biosignature science as of October 2026: JWST atmosphere results for giant and rocky planets, the disputed dimethyl sulfide claim for the sub-Neptune K2-18 b, and the stellar-contamination and model-degeneracy problems that limit rocky-planet tests. The main takeaway is that no biosignature gas has been confirmed and the leading claims remain contested.","version":1,"published_at":"2026-10-30","updated_at":"2026-10-30","stats":{"words":4114,"citations":54,"claims":29,"timeline":18,"benchmarks":12,"open_problems":7,"key_papers":14,"glossary":13},"verification":{"status":"verified","method":"automated figure and citation-relevance triage against cited abstracts, targeted AI review with web checks of flagged statements, and a close-out pass hedging or removing unconfirmed statements; automated citation resolution","claims_checked":29,"issues_fixed":4,"verified_at":"2026-10-30"},"ai_assisted":true,"price":{"usd":"0.20","protocol":"x402","network":"eip155:84532","asset":"USDC"},"url":"https://space-kitty.com/dossiers/exoplanets-biosignatures","preview_url":"https://space-kitty.com/api/v1/dossiers/exoplanets-biosignatures/preview","purchase_url":"https://space-kitty.com/api/v1/dossiers/exoplanets-biosignatures","toc":[{"level":2,"text":"Executive summary","anchor":"executive-summary"},{"level":2,"text":"Background and core concepts","anchor":"background-and-core-concepts"},{"level":2,"text":"Timeline of key milestones","anchor":"timeline-of-key-milestones"},{"level":2,"text":"State of the art","anchor":"state-of-the-art"},{"level":3,"text":"Giant and warm planets: photochemistry, clouds and haze","anchor":"giant-and-warm-planets-photochemistry-clouds-and-haze"},{"level":3,"text":"Temperate sub-Neptunes: the K2-18 b test case","anchor":"temperate-sub-neptunes-the-k2-18-b-test-case"},{"level":3,"text":"Rocky planets around M dwarfs","anchor":"rocky-planets-around-m-dwarfs"},{"level":3,"text":"Stellar contamination and retrieval methods","anchor":"stellar-contamination-and-retrieval-methods"},{"level":3,"text":"Biosignature theory and false positives","anchor":"biosignature-theory-and-false-positives"},{"level":3,"text":"Quantitative benchmarks","anchor":"quantitative-benchmarks"},{"level":2,"text":"Open problems and active debates","anchor":"open-problems-and-active-debates"},{"level":2,"text":"Major programs and players","anchor":"major-programs-and-players"},{"level":2,"text":"Outlook: what to watch (next 12-18 months)","anchor":"outlook-what-to-watch-next-12-18-months"},{"level":2,"text":"Key papers","anchor":"key-papers"},{"level":2,"text":"Glossary","anchor":"glossary"}],"sample_claims":["JWST transmission spectra of WASP-39b show an absorption feature at 4.05 μm attributed to photochemically produced SO2.","Thermochemical equilibrium predicts SO2 below 1 ppb in WASP-39b, while photochemistry of H2O and H2S yields 1–10 ppm."],"includes":["markdown","claims","timeline","benchmarks","open_problems","key_papers","glossary","bibliography"],"citation_count":54,"how_to_buy":"GET https://space-kitty.com/api/v1/dossiers/exoplanets-biosignatures with an x402 client ($0.20, USDC on Base Sepolia (testnet))."}