{"paper":{"title":"An extremely primitive halo star","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.GA","authors_text":"2), (2) GEPI - Obs. de Paris, 2). L. Monaco (5), 3). L. Sbordone (1, (3) Univ. de Picardie Jules Verne, 4, (4) Max Planck Institut f\\\"ur Astrophysik, (5) ESO - Santiago, (6) INAF - Osservatorio Astronomico di Padova, (7) INAF - Osservatorio Astrofisico di Arcetri, (8) INAF - Osservatorio Astronomico di Trieste, (9) Univ. de Nice Sophia Antipolis, CNRS, E. Caffau (1, F. Hammer (2), F. Spite (2), H.-G. Ludwig (1, Lab. Cassiop\\'ee), M. Spite (2), OCA, P. Bonifacio (2), P. Fran\\c{c}ois (2, P. Molaro (8), R. Cayrel (2), S. Randich (7), S. Zaggia (6), Univ. Paris Diderot, V. Hill (9)((1) ZAH-LSW Heidelberg","submitted_at":"2012-03-12T20:00:03Z","abstract_excerpt":"The early Universe had a chemical composition consisting of hydrogen, helium and traces of lithium1, almost all other elements were created in stars and supernovae. The mass fraction, Z, of elements more massive than helium, is called \"metallicity\". A number of very metal poor stars have been found some of which, while having a low iron abundance, are rich in carbon, nitrogen and oxygen. For theoretical reasons and because of an observed absence of stars with metallicities lower than Z=1.5E-5, it has been suggested that low mass stars (M<0.8M\\odot, the ones that survive to the present day) can"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1203.2612","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"}