{"paper":{"title":"A Rare Population of Intermediate-mass Helium Stars Between Hot Subdwarfs and Wolf-Rayet Stars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Binary population synthesis predicts several thousand intermediate-mass helium stars in the Milky Way.","cross_cats":["astro-ph.HE"],"primary_cat":"astro-ph.SR","authors_text":"Gui-Yu Wang, Jian-Guo He, Xiang-Dong Li, Xiao-jie Xu, Yong Shao, Yu-Dong Nie","submitted_at":"2026-05-16T02:18:25Z","abstract_excerpt":"Helium stars stripped of their hydrogen envelopes represent pivotal phases in binary evolution, yet their origins, particularly within the intermediate-mass range of $2-8\\, M_{\\odot}$, still remain poorly understood. This population bridges the gap between low-mass hot subdwarfs and massive Wolf-Rayet stars, but has remained largely unobserved. In this study, we employ binary population synthesis to systematically investigate the formation and properties of intermediate-mass helium stars (IMHeS) across various galactic metallicities. Our results indicate that metallicity and common-envelope ej"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We estimate that several thousand IMHeS exist in the Milky Way, with several hundred more in the Magellanic Clouds. The vast majority of IMHeS reside in binaries, with fewer than 10% appearing as single stars.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The binary population synthesis framework and its standard prescriptions for mass transfer stability and common-envelope ejection accurately represent the physics governing stars in the 2-8 solar mass range across metallicities.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Binary population synthesis predicts several thousand intermediate-mass helium stars in the Milky Way, mostly in binaries, with metallicity and common-envelope ejection efficiency as the dominant shaping factors.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Binary population synthesis predicts several thousand intermediate-mass helium stars in the Milky Way.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"0888a51dbc3d5890a212c98f0d4df1dcc534d37355c7121ccfb9daa15a416776"},"source":{"id":"2605.16760","kind":"arxiv","version":1},"verdict":{"id":"28afb5bf-e200-4d56-82ed-1caf9a46014b","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-19T20:17:32.915504Z","strongest_claim":"We estimate that several thousand IMHeS exist in the Milky Way, with several hundred more in the Magellanic Clouds. The vast majority of IMHeS reside in binaries, with fewer than 10% appearing as single stars.","one_line_summary":"Binary population synthesis predicts several thousand intermediate-mass helium stars in the Milky Way, mostly in binaries, with metallicity and common-envelope ejection efficiency as the dominant shaping factors.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The binary population synthesis framework and its standard prescriptions for mass transfer stability and common-envelope ejection accurately represent the physics governing stars in the 2-8 solar mass range across metallicities.","pith_extraction_headline":"Binary population synthesis predicts several thousand intermediate-mass helium stars in the Milky Way."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.16760/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"doi_compliance","ran_at":"2026-05-19T20:32:04.075638Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_title_agreement","ran_at":"2026-05-19T20:31:19.158983Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"claim_evidence","ran_at":"2026-05-19T19:01:56.319646Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"ai_meta_artifact","ran_at":"2026-05-19T18:33:26.451678Z","status":"skipped","version":"1.0.0","findings_count":0}],"snapshot_sha256":"df8c3c059b2febb2c621f28731f6da7fc32d7c797a7bd33609d71ebd680e55ae"},"references":{"count":83,"sample":[{"doi":"10.3847/2041-8213/ad5beb","year":2024,"title":"Observation of Gravitational Waves from the Coalescence of a 2.5–4.5 M ⊙ Compact Object and a Neutron Star.Astrophys","work_id":"f90e9e10-dde4-4de7-a0fd-36a70ee2aacc","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1088/0004-637x/714/2/1217","year":2010,"title":"Belczynski, K., Bulik, T., Fryer, C. L., et al. 2010, On the Maximum Mass of Stellar Black Holes, ApJ, 714, 1217, doi: 10.1088/0004-637X/714/2/1217","work_id":"2771dc66-bf87-4481-ad40-d11c6063c42e","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1088/1538-3873/ae3a19","year":2026,"title":"R., & G¨ otberg, Y","work_id":"5facf88b-ab03-4465-b737-4f7c013d88be","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1051/0004-6361/201732493","year":2018,"title":"Breddels, M. A., & Veljanoski, J. 2018, Vaex: big data exploration in the era of Gaia, A&A, 618, A13, doi: 10.1051/0004-6361/201732493","work_id":"8b85687c-c27b-4120-bf33-24bff92f1b1f","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1086/175268","year":1995,"title":"Brown, G. E. 1995, Neutron Star Accretion and Binary Pulsar Formation, ApJ, 440, 270, doi: 10.1086/175268","work_id":"db77ad03-f5a7-495d-8f23-0b0ad72a0a8b","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":83,"snapshot_sha256":"e408db7a315a0e1ebba8c3b1405c35285a8a52af9c413ed8aa17d610e29de6dd","internal_anchors":1},"formal_canon":{"evidence_count":1,"snapshot_sha256":"c702f41a0b32ecedba3f040ffc56dfda7b951215dd0b8baf0f4498f2932d8b7c"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}