{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e88ae46ed8a3950d73a3d3feee3230aacb0651f280fe5dbde3683b7d5b0bdce7","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"b07c1ada12a0b7bf7f4509776ff48a126cbd24bc04c9ab09321ba0f9eca11bac","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.accretion-jet-launching.radiation-pressure-instability","kind":"phenomenon","literature_status":"open","n":"1","parents":[],"plain":"Theory from the 1970s predicts that disks held up mostly by the pressure of light should heat up and fall apart unstably, yet many bright disks look steady.","posed_since":"1974","precise":"Standard alpha disks in which radiation pressure exceeds gas pressure, with stress proportional to total pressure, are thermally and viscously unstable (Lightman-Eardley), predicting limit cycles; most X-ray binaries in the soft state at $L \\sim 0.1 \\text{ to } 0.5\\,L_{\\mathrm{Edd}}$ show stable disk emission, with GRS 1915+105 and a few others as exceptions. Determine the stabilizing physics (magnetic pressure support, opacity effects, stress scaling with gas pressure). Answer: a mechanism and stability criterion matching which sources vary and which do not.","problem_ref":null,"references":"","settled_by":"Radiation-MHD simulations predicting stability boundaries that match the observed luminosity at which limit-cycle variability appears.","status_note":"","title":"Why do radiation-dominated accretion disks appear thermally stable?","topic_ref":"c6622c49671f85d956e06199b59037776536a6db727b79f3ac01839ce91af768"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a75c840a29484a5749dc96dd9957fab76b0c6c21490190acbeef83a6c5c3a790","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"47f043d68b01a8ebaca620d3097624655a8f4b38fd4c95630b832c7cfd077030","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"wpiAgFflECjkJOJSwMlqxcCJZ_3JTfFOz1qRMfCJ2p3KcafN5oZbu_pP_FHfNJoqvOzNI3__YpkKOvKc9kB7Aw"},"schema":"pubphys.envelope/1"},"record_hash":"a75c840a29484a5749dc96dd9957fab76b0c6c21490190acbeef83a6c5c3a790","leaf_index":482}