{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3af3cb17e10eb623ced46cc0109a32f89f3399dade1a7f8f4998bbac70176289","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"f41d822f5035be91b775ac42f59798711e9a36081cc234c7a5e768ee7e97713b","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.ism-astrochemistry.cold-cloud-pahs","kind":"phenomenon","literature_status":"open","n":"1","parents":[],"plain":"Radio telescopes have found large ring-shaped carbon molecules and other complex organics in a dark cloud only about 10 degrees above absolute zero. Chemistry models predict far smaller amounts than are seen.","posed_since":"2021","precise":"In TMC-1 (T ~ 10 K, n_H2 ~ 1e4 cm^-3) radio spectroscopy has detected complex organic molecules and cyano-substituted polycyclic aromatic hydrocarbons (cyanonaphthalenes, 2021; cyanopyrene, 2024; cyanocoronene, 2025) at abundances orders of magnitude above bottom-up gas-grain models. Identify the formation pathways (barrierless gas-phase growth, grain-surface chemistry with nonthermal desorption, or inheritance from an earlier phase) that reproduce the observed abundances.","problem_ref":null,"references":"","settled_by":"A chemical network with laboratory-measured rate coefficients that reproduces the observed PAH and organic abundances in TMC-1 at its estimated age.","status_note":"","title":"How do complex organics and aromatic molecules form in cold clouds?","topic_ref":"053938143b301dc6b1d81522aef24ce54269bd5a5c046d77683dda38966086a5"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"15c9b92dca14bec0e568942c8c509dcbd43155bc0e3b78294385afa893641a60","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"a5ae7cf8c51d421594ecb75e94ed686c35d7cd31735e9cecd6c3021e8268bbd7","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"FcrBaun3RV5nb7yQ_4Z_P99nBAjLICN4buhskKICkqw4tH0YFwv76VxnlDfKg6W2CDSj3mkwiix_MiMPFJ9uBA"},"schema":"pubphys.envelope/1"},"record_hash":"15c9b92dca14bec0e568942c8c509dcbd43155bc0e3b78294385afa893641a60","leaf_index":566}