{"paper":{"title":"The compact neutron star in 4U 1746-37 revisited: Reassessing the mass and radius","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"Significant X-ray flux blocking allows the neutron star in 4U 1746-37 to match standard mass and radius values.","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.HE","authors_text":"Chang-Hwan Lee, Kwang Hyun Sung, Kyujin Kwak, Myungkuk Kim, Young-Min Kim","submitted_at":"2026-05-14T02:08:14Z","abstract_excerpt":"A recent analysis of photospheric radius expansion X-ray bursts from the low-mass X-ray binary 4U 1746-37 reported unusually small mass and radius estimates for the neutron star, suggesting it could be a quark star or quark-cluster star. Here, we propose an alternative interpretation: the star's mass and radius could be underestimated from significant blocking of the X-ray flux. Significant blocking factors ($\\mathcal{B} \\gtrsim 0.8$, reducing the observed flux to $\\sim17\\%$ of the intrinsic emission) permit neutron star parameters consistent with the canonical values: $M = 1.59 \\pm 0.69 M_{\\o"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Significant blocking factors (B ≳ 0.8, reducing the observed flux to ∼17% of the intrinsic emission) permit neutron star parameters consistent with the canonical values: M = 1.59 ± 0.69 M⊙, R = 13.0 ± 5.45 km, or M = 2.12 ± 1.08 M⊙, R = 9.80 ± 4.13 km.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that significant flux blocking (B ≳ 0.8) occurs and varies with photospheric radius, thereby explaining the anomalously large peak-to-touchdown flux ratio of ∼2.0.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Significant X-ray flux blocking in 4U 1746-37 allows the neutron star to have canonical mass and radius values of 1.59 solar masses and 13 km or 2.12 solar masses and 9.8 km.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Significant X-ray flux blocking allows the neutron star in 4U 1746-37 to match standard mass and radius values.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"0247f6270a9377ffe0e79e2853956839a65fb732bc98551942258676e9d0a2bd"},"source":{"id":"2605.14264","kind":"arxiv","version":1},"verdict":{"id":"53ff4c22-1b6e-476c-8a86-9a2cc592e8b8","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T02:18:19.479243Z","strongest_claim":"Significant blocking factors (B ≳ 0.8, reducing the observed flux to ∼17% of the intrinsic emission) permit neutron star parameters consistent with the canonical values: M = 1.59 ± 0.69 M⊙, R = 13.0 ± 5.45 km, or M = 2.12 ± 1.08 M⊙, R = 9.80 ± 4.13 km.","one_line_summary":"Significant X-ray flux blocking in 4U 1746-37 allows the neutron star to have canonical mass and radius values of 1.59 solar masses and 13 km or 2.12 solar masses and 9.8 km.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that significant flux blocking (B ≳ 0.8) occurs and varies with photospheric radius, thereby explaining the anomalously large peak-to-touchdown flux ratio of ∼2.0.","pith_extraction_headline":"Significant X-ray flux blocking allows the neutron star in 4U 1746-37 to match standard mass and radius values."},"references":{"count":114,"sample":[{"doi":"","year":2013,"title":"Antoniadis, J. et al. 2013, Science, 340, 6131","work_id":"5f4a3420-fd7d-4118-bd88-d6f093bf6485","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1934,"title":"& Zwicky , F","work_id":"7a8e8670-53ee-448a-b683-be44ae2cad09","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2009,"title":"2009, , 138, 50","work_id":"e8742929-3175-4e62-85a2-129e5462ec01","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2004,"title":"J., & Smale , A","work_id":"7ed0061d-25d5-4467-b0b0-539c6d6a4889","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1971,"title":"1971, , 170, 299","work_id":"dd3f77af-4cef-4a43-b0a4-d31364fae201","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":114,"snapshot_sha256":"c48880927c5110ecafebbd00fc178b3d0b71ebfe908ead91c75be974166e9562","internal_anchors":32},"formal_canon":{"evidence_count":2,"snapshot_sha256":"13644812d925b4a3df7ccf93d8b84704a6c7e5858f143c1530ff66f91dba140c"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}