{"paper":{"title":"Evidence for a bloated massive protostar in IRAS20126+4104","license":"http://creativecommons.org/licenses/by/4.0/","headline":"The 12 solar-mass protostar in IRAS20126+4104 is bloated to a radius of about 200 solar radii.","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.SR","authors_text":"Riccardo Cesaroni","submitted_at":"2026-04-14T10:29:14Z","abstract_excerpt":"Variability is a well known phenomenon in low-mass young stellar objects, but in recent years the monitoring of methanol masers and infrared continuum emission has permitted the detection of both burst-like episodes and periodic variations also in high-mass (proto)stars. Multi-epoch studies on large samples of these objects have become possible thanks to the NEOWISE database, which surveyed the sky in the mid-IR for about a decade. Our goal is to analyse the mid-IR emission from the well studied massive protostar IRAS20126+4104 and confirm the hypothesis that such emission is periodic, as prop"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The long rotation period implies that the 12 M_⊙ protostar is bloated, with a radius of ∼200 R_⊙.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the observed 6.8 yr periodicity is produced by stellar rotation with a surface spot rather than any of the other three clocks considered, and that the 12 M_⊙ mass and spot geometry allow a direct conversion from period to radius.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Mid-IR light curves of IRAS20126+4104 confirm a 6.8 yr periodic variation interpreted as evidence that the 12 solar-mass protostar is bloated to a radius of roughly 200 solar radii due to rotation with an obscuring spot.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The 12 solar-mass protostar in IRAS20126+4104 is bloated to a radius of about 200 solar radii.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"cf09bef5033f98d8ff06aaf9ddb8bae5a05ab3490f716b1361a5532bfc5ed125"},"source":{"id":"2604.12552","kind":"arxiv","version":1},"verdict":{"id":"62dce52a-56f4-4549-82e1-f1a68012c3ec","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T15:04:33.966816Z","strongest_claim":"The long rotation period implies that the 12 M_⊙ protostar is bloated, with a radius of ∼200 R_⊙.","one_line_summary":"Mid-IR light curves of IRAS20126+4104 confirm a 6.8 yr periodic variation interpreted as evidence that the 12 solar-mass protostar is bloated to a radius of roughly 200 solar radii due to rotation with an obscuring spot.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the observed 6.8 yr periodicity is produced by stellar rotation with a surface spot rather than any of the other three clocks considered, and that the 12 M_⊙ mass and spot geometry allow a direct conversion from period to radius.","pith_extraction_headline":"The 12 solar-mass protostar in IRAS20126+4104 is bloated to a radius of about 200 solar radii."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.12552/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":37,"sample":[{"doi":"","year":2002,"title":"A., Levato, H., & Grosso, M","work_id":"c51d585f-3b6b-4110-a126-be4606bc7f08","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1997,"title":"1997, A&A, 325, 725","work_id":"4cad5f5e-1ae8-4d77-888f-a1877e34b180","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2005,"title":"2005, A&A, 434, 1039 Cesaroni R., Galli D., Neri R., & Walmsley C","work_id":"712b821f-5dc8-4f97-8e59-9652ae79657f","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"2023, A&A, 671, A126","work_id":"70862462-16cc-47da-b514-07db873c933f","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2025,"title":"M., & Sánchez-Monge, Á","work_id":"01a60bcd-ea2a-42ae-900f-fd36f212bf25","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":37,"snapshot_sha256":"fd4a0af4ade9f3ad360f8ed9bf5e7c13214f440a13d7bca81f1fb8d985a6e605","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}