{"paper":{"title":"Pre-main Sequence B Stars Surrounding the Orion Nebula","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"A. E. Piatti, A. Roman-Lopes, E. B. Am\\^ores, F. S. S. Maia, J. F. C. Santos Jr., M. S. Angelo, P.H.F.B. Braz, W.J.B. Corradi, W. Reis","submitted_at":"2026-07-16T19:22:13Z","abstract_excerpt":"Pre-main sequence (PMS) early-type stars are rare due to their rapid evolution. Confirming PMS B stars is accordingly valuable for constraining higher mass star formation scenarios. Although the Orion Nebula (ON) region offers an ideal laboratory for such studies, its population of B stars remains poorly characterized. We aim to determine spectral types, masses, and ages of B and early A stars surrounding the ON, to identify robust PMS candidates. We combine optical and near-infrared spectroscopy to estimate spectral types using Brackett, He, Si, and Mg lines. Photometry from Gaia, 2MASS, and "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.15409","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.15409/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}