{"paper":{"title":"The forgotten bright star: Theta Eridani as a millenary stellar transient observed by Hipparchus, Ptolemy and al-Sufi","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["physics.hist-ph"],"primary_cat":"astro-ph.SR","authors_text":"Boaz Katz, Idel Waisberg","submitted_at":"2026-06-29T18:00:19Z","abstract_excerpt":"Theta Eridani is a V=2.9 star that was nonetheless reported as one of the thirteen brightest stars in the night sky by both Ptolemy in his Almagest (137 AD) and by al-Sufi in his The Book of Fixed Stars (964 AD), in addition to being previously referred by Hipparchus (129 BC) as a particularly bright star. The discrepancy between its historical and modern visual magnitude $\\Delta V \\sim 2.7$ is the highest among the $\\sim 1000$ stars in the Almagest. Theta Eridani is actually a triple star system, and here we combine interferometric data from VLTI/PIONIER and VLTI/GRAVITY, spectroscopic data f"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.30748","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/2606.30748/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"}