{"paper":{"title":"The age of old Magelanic Cloud clusters. I: NGC 2257.","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"E. Brocato, F.R.Ferraro, V. Castellani, V.Testa","submitted_at":"1995-03-27T15:10:44Z","abstract_excerpt":"Deep CCD photometry down to V=24.5 is presented for the old Magellanic Globular cluster NGC 2257. The main result cna be summarized as follows: i) the RGB Bump has been detected at V=18.7+-0.1, and is compatible with determination of this feature in GGCs; ii) NGC 2257 seems to be 2-3 Gyrs younger than a typical GGC; iii) the helium abundance has been estimated to be Y=0.21+-0.03, using the R- method as calibrated by Buzzoni et al., 1983."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/9503097","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"}