{"case":{"id":"OS-0035","title":"Two large infrared eruptions 14 years apart in an HII region of M81, the second in 2024","hook":"Found by Oddsky's infrared searches of nearby galaxies (hunts H-0012 and H-0013): an obscured source in M81 erupted by 2009 and again in 2023-24, each time reaching about 3e5 L_sun in the infrared, with nothing seen between.","status":"reproduced","target":{"name":"M81 recurrent IR outburst","ra":148.73908,"dec":69.14676,"aliases":[]},"summary":"An obscured source in an HII region of M81 (3.6 Mpc) that erupted in the infrared by 2009 and again in 2023-24, each time reaching about 3e5 L_sun, with nothing between. Probably recurrent eruptions of a massive star; a long-period dust maker or two unrelated events are possible. Post-2024 infrared data would tell. Found by Oddsky hunts H-0012 and H-0013.","claims":[{"id":"C1","text":"Spitzer: flat 2003.8-2005.0, then +196 uJy at 2009.9 declining to +98 uJy by 2010.4; WISE 2010 agrees (hunts/H-0013/README.md).","tag":"observed","calls":[],"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"},{"id":"C2","text":"WISE: flat 2014-2023, then a sharp rise in 2023.9-2024.4 to W1 0.75 / W2 1.0 mJy (about 3e5 L_sun at 3.6 Mpc). H-0012 v2 ranks it 8th among obscured transients (hunts/H-0012/work/triage_h0012b.csv).","tag":"observed","calls":[],"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"},{"id":"C3","text":"It sits on a giant molecular cloud / HII region next to a blue Gaia source (G = 20.25, BP-RP = 0.37, M_G about -7.5); the nearest TNS object is AT 2026dvq, 22.6\" away.","tag":"observed","calls":[],"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"},{"id":"C4","text":"Not reported (2026-11-02): ADS full text for the coordinates and for the host with variability terms finds nothing on this source; nothing in TNS, SIMBAD, Gaia DR3, AllWISE or the Spitzer SEIP catalogue at the position; nothing within 10\" in the SPIRITS catalogue of luminous long-period variables, which covers M81.","tag":"observed","calls":[],"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"}],"hypotheses":[{"id":"H1","klass":"eruptive","statement":"Recurrent eruptions of a massive star (LBV-like), each forming or heating dust.","supports":["C1","C2","C3"],"conflicts":[],"would_falsify":"A post-2024 infrared decline with a supernova-like spectrum, or a third outburst inconsistent with one star.","status":"live","confidence":0.5,"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"},{"id":"H2","klass":"dust_formation","statement":"A long-period (about 16 yr) dust-forming binary.","supports":["C1","C2"],"conflicts":[],"would_falsify":"No outburst near 2039-2040.","status":"live","confidence":0.25,"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"},{"id":"H3","klass":"artifact_blend","statement":"Two unrelated transients in the same HII region.","supports":["C3"],"conflicts":[],"would_falsify":"Further outbursts from the same point.","status":"live","confidence":0.15,"author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00"}],"predictions":[],"literature":[],"hunt":"H-0013","featured":false,"created_at":"2026-11-02T21:36:38+00:00"},"series":{},"context":{},"provenance":{},"skeptic":null,"ledger":[{"id":"K1","tool":"add_claim","args":{"id":"C1","tag":"observed"},"digest":"47420e4be8ce39a8","digest10":"47420e4be8ce39a8","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K2","tool":"add_claim","args":{"id":"C2","tag":"observed"},"digest":"810fe66681869023","digest10":"810fe66681869023","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K3","tool":"add_claim","args":{"id":"C3","tag":"observed"},"digest":"a8e3dde17ac83cf1","digest10":"a8e3dde17ac83cf1","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K4","tool":"add_claim","args":{"id":"C4","tag":"observed"},"digest":"a75fcb10446e9d88","digest10":"a75fcb10446e9d88","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K5","tool":"add_hypothesis","args":{"id":"H1","klass":"eruptive"},"digest":"a3afdee2a580e9e9","digest10":"a3afdee2a580e9e9","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K6","tool":"add_hypothesis","args":{"id":"H2","klass":"dust_formation"},"digest":"3c8ab29249da19db","digest10":"3c8ab29249da19db","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"},{"id":"K7","tool":"add_hypothesis","args":{"id":"H3","klass":"artifact_blend"},"digest":"98cd99168b0a91ec","digest10":"98cd99168b0a91ec","author":"claude-opus-5.5","at":"2026-11-02T21:36:38+00:00","oddsky":"0.3.1","platform":"darwin-arm64"}],"investigations":[],"reviews":[]}