{"paper":{"title":"BE Lyncis: A Pulsating Star in the Most Eccentric Binary with a Massive Unseen Companion","license":"http://creativecommons.org/licenses/by/4.0/","headline":"BE Lyncis is a delta Scuti star in the most eccentric binary known, hosting a likely black hole companion of at least 2.5 solar masses.","cross_cats":["astro-ph.HE"],"primary_cat":"astro-ph.SR","authors_text":"Hui-Fang Xue, Jia-Shu Niu, Ying Zhang","submitted_at":"2026-01-19T12:25:59Z","abstract_excerpt":"We report the discovery of an exceptionally eccentric binary system, BE Lyncis (BE Lyn), which might host a compact companion with mass $\\gtrsim 2.5~M_{\\odot}$. By combining TESS photometry with an extensive set of times of maximum light spanning 39 years, we identify BE Lyn as a high-amplitude $\\delta$ Scuti star in a binary with an orbital period of $\\approx15.9$ years and an extraordinary eccentricity of $e=0.9989^{+0.0008}_{-0.0021}$ ($>0.9968$ at 95% confidence) -- the most extreme eccentricity reliably measured for any binary system. Dynamical constraints limit the orbital inclination to"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"BE Lyn is a high-amplitude δ Scuti star in a binary with orbital period ≈15.9 years and eccentricity e=0.9989^{+0.0008}_{-0.0021} (>0.9968 at 95% confidence), the most extreme reliably measured, with dynamical constraints implying i ≲ 10.1° and companion mass M2 ≳ 2.5 M⊙, most likely a black hole.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The light-travel time effect from the binary orbit fully accounts for the observed times of maximum light without significant contributions from other effects such as apsidal motion, mass transfer, or intrinsic period changes in the pulsator, and that the fitted orbital elements uniquely constrain the inclination to ≲10.1°.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"BE Lyncis is the most eccentric binary known, a pulsating star with a massive compact companion of at least 2.5 solar masses inferred to be a black hole at very low orbital inclination.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"BE Lyncis is a delta Scuti star in the most eccentric binary known, hosting a likely black hole companion of at least 2.5 solar masses.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"f4ea13d23f9f1aa10ce93dfcf9b35d8652ea32dbb8c33a288d34772dc59e0467"},"source":{"id":"2601.12999","kind":"arxiv","version":4},"verdict":{"id":"15516857-0d45-4961-8479-d147b1545531","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T13:15:23.411791Z","strongest_claim":"BE Lyn is a high-amplitude δ Scuti star in a binary with orbital period ≈15.9 years and eccentricity e=0.9989^{+0.0008}_{-0.0021} (>0.9968 at 95% confidence), the most extreme reliably measured, with dynamical constraints implying i ≲ 10.1° and companion mass M2 ≳ 2.5 M⊙, most likely a black hole.","one_line_summary":"BE Lyncis is the most eccentric binary known, a pulsating star with a massive compact companion of at least 2.5 solar masses inferred to be a black hole at very low orbital inclination.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The light-travel time effect from the binary orbit fully accounts for the observed times of maximum light without significant contributions from other effects such as apsidal motion, mass transfer, or intrinsic period changes in the pulsator, and that the fitted orbital elements uniquely constrain the inclination to ≲10.1°.","pith_extraction_headline":"BE Lyncis is a delta Scuti star in the most eccentric binary known, hosting a likely black hole companion of at least 2.5 solar masses."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2601.12999/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":1,"snapshot_sha256":"22763cdb22c52ad72e6fb9a0683e30dd330965cf06276f8e3b0ab08b415b15c2"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}