{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"5677d19f5dba7262ef1c0d4f8ce8748d960d92302b894de1255e1df4ac8a2d17","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["a93dbffe220d30a4b58ec3f954224252cf872d031a35eb4ca93b771da0e09cb0","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"8dcf04ad616137e6499539d2f32265e89cfe35b4b9ca8a6901ea7d8c95362c5d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":["ai:gpt-5.5"],"external_id":"astro.core-collapse-supernovae.precursor-mass-loss","kind":"phenomenon","literature_status":"open","n":"2","parents":[],"plain":"Many supernovae explode into thick gas that the star shed only years to decades before dying, far more than normal stellar winds can explain.","posed_since":"","precise":"Early spectra with narrow, short-lived emission lines (flash ionization) show dense circumstellar material within $\\sim 10^{15}\\,\\mathrm{cm}$ in a large fraction of Type II supernovae, implying mass-loss rates $\\sim 10^{-4}$ to $10^{-2}$ $M_{\\mathrm{sun}}/\\mathrm{yr}$ in the last years, far above steady red supergiant winds of $\\sim 10^{-6}$ $M_{\\mathrm{sun}}/\\mathrm{yr}$. Identify the mechanism (wave energy transport from core convection in the last burning stages, binary interaction, pulsation-driven winds) and whether it also produces observed pre-explosion outbursts. Answer: a mechanism predicting circumstellar mass and extent versus progenitor mass and evolutionary stage.","problem_ref":"a93dbffe220d30a4b58ec3f954224252cf872d031a35eb4ca93b771da0e09cb0","references":"","settled_by":"Pre-explosion monitoring of many nearby supernova progenitors combined with early spectra, compared with predicted outburst timing and circumstellar masses.","status_note":"2023: SN 2023ixf in M101, the nearest Type II supernova in a decade, showed dense, confined circumstellar material.","title":"What drives heavy mass loss in the final years before collapse?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"02dc1ca09b00b50fa80d0fd81eea5e4bb29509e9ebe927860eb32fd1d17a0513","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4227e619288667aecfd64308cbedc5b6249872538a919298c2ad06b5ee2679be","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"nS5ZcJdFdHp0euGZRyc5_XwMaloXNHSeRmTV4xEUeHdMBF0-Q9bhtDHR1tLDBKujb1TQndVflNwO8U3zfmaXBA"},"schema":"pubphys.envelope/1"},"record_hash":"02dc1ca09b00b50fa80d0fd81eea5e4bb29509e9ebe927860eb32fd1d17a0513","leaf_index":2324}