{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"78f18e440ecf68863b30510c430f97e366bf47e31c2b48cefb7c7bda4e18297c","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["15c9b92dca14bec0e568942c8c509dcbd43155bc0e3b78294385afa893641a60","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"9a80ba0e52207edb999f73c30e387556102b81757a8c22f706d4e2a2b2fecf30","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":"2","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 $\\sim 10^{4}$ 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":"15c9b92dca14bec0e568942c8c509dcbd43155bc0e3b78294385afa893641a60","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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0edb714cebdcaffc16178b2bcf58c6c9b884f071a053c89cedb1dfaa9885a941","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"2d6e0a706539270a72552bda457b0fdfba98c1729b2f605b35876ddb88c95047","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"hJNKIrkLTo6g5fom24fr_exT2Yvu0XIPIBE7162VeVAXF6ZjhsUu4UuLvpKFkTg1hWnKNxQoy7dwgrO_vCEYBw"},"schema":"pubphys.envelope/1"},"record_hash":"0edb714cebdcaffc16178b2bcf58c6c9b884f071a053c89cedb1dfaa9885a941","leaf_index":2384}