{"paper":{"title":"Chemical abundances and radial velocities in the extremely metal-poor galaxy DDO 68","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"(2) Dipartimento di Fisica e Astronomia, (3) Space Telescope Science Institute, (4) INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, A. Aloisi (3), A. Marchetti (4), Baltimore, Bologna, C. Nipoti (2), D. Romano (1), E. Sacchi (3) ((1) INAF-Osservatorio di Astrofisica e Scienza dello Spazio, F. Annibali (1), F. Cusano (1), Italy, Italy), L. Ciotti (2), M. Bellazzini (1), Milano, M. Mignoli (1), M. Tosi (1), Universit\\`a di Bologna, USA, V. La Torre (2)","submitted_at":"2018-10-05T18:01:20Z","abstract_excerpt":"We present chemical abundances and radial velocities of six HII regions in the extremely metal-poor star-forming dwarf galaxy DDO 68. They are derived from deep spectra in the wavelength range 3500 - 10,000 {\\AA}, acquired with the Multi Object Double Spectrograph (MODS) at the Large Binocular Telescope (LBT). In the three regions where the [O III]$\\lambda$4363 {\\AA} line was detected, we inferred the abundance of He, N, O, Ne, Ar, and S through the \"direct\" method. We also derived the oxygen abundances of all the six regions adopting indirect method calibrations. We confirm that DDO 68 is an "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1810.02830","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"}