{"paper":{"title":"Discovery of the massive overcontact binary VFTS 352: Evidence for enhanced internal mixing","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"A. Damineli, A. de Koter, A. Herrero, C. Norman, F. Tramper, G. Gr\\\"afener, H. Sana, I. Howarth, I. Soszy\\'nski, J. Ma\\'iz Apell\\'aniz, J.S. Vink, L.A. Almeida, M. Cantiello, M. Garcia, N. Langer, O.H. Ram\\'irez-Agudelo, R.H. Barb\\'a, S.E. de Mink","submitted_at":"2015-09-29T20:17:53Z","abstract_excerpt":"The contact phase expected to precede the coalescence of two massive stars is poorly characterized due to the paucity of observational constraints. Here we report on the discovery of VFTS 352, an O-type binary in the 30 Doradus region, as the most massive and earliest spectral type overcontact system known to date. We derived the 3D geometry of the system, its orbital period $P_{\\rm orb}=1.1241452(4)$ d, components' effective temperatures -- $T_1=42\\,540\\pm280$ K and $T_2=41\\,120\\pm290$ K -- and dynamical masses -- $M_1=28.63\\pm0.30 M_{\\odot}$ and $M_2 = 28.85\\pm0.30 M_{\\odot}$. Compared to si"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.08940","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","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"}