{"paper":{"title":"Hyperaccreting Neutron Stars inside Massive Envelopes: The Implausibility of Thorne-\\.Zytkow Objects","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Simulations show neutron stars in massive stellar envelopes accrete rapidly and collapse to black holes rather than forming stable Thorne-Zytkow objects.","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Christopher L. Fryer, David Radice, Patrick Chi-Kit Cheong","submitted_at":"2026-04-26T02:36:37Z","abstract_excerpt":"The evolution of neutron stars (NSs) embedded within massive stellar envelopes is a critical phase in binary stellar evolution, potentially leading to the formation of Thorne-\\.Zytkow Objects (T\\.ZOs) or catastrophic collapse. We present the first fully coupled general relativistic hydrodynamics (GRHD) simulations of hypercritical accretion onto NSs that simultaneously incorporate grey two-moment (M1) neutrino transport and an $\\alpha$-chain nuclear reaction network. By investigating four distinct progenitor evolutionary stages, we resolve the complex interplay between intense neutrino cooling"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We conclude that these systems are not stable T.ZOs, but are rather transient precursors to catastrophic black hole formation and potential central engines for high-energy transients.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the grey two-moment (M1) neutrino transport scheme combined with the α-chain nuclear network and the chosen progenitor models fully capture the relevant physics without missing effects such as magnetic fields or more detailed neutrino interactions that could enable outflows.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Hypercritical accretion onto neutron stars embedded in massive envelopes leads to rapid collapse into black holes rather than stable Thorne-Zytkow objects.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Simulations show neutron stars in massive stellar envelopes accrete rapidly and collapse to black holes rather than forming stable Thorne-Zytkow objects.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"05ffe6d440bd50046b91b1406a85df68a3f339f382a143d371bfb5d2820949e2"},"source":{"id":"2604.23503","kind":"arxiv","version":2},"verdict":{"id":"393d802c-fd9e-4b51-b664-4d87ff6e4004","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-08T05:41:14.746130Z","strongest_claim":"We conclude that these systems are not stable T.ZOs, but are rather transient precursors to catastrophic black hole formation and potential central engines for high-energy transients.","one_line_summary":"Hypercritical accretion onto neutron stars embedded in massive envelopes leads to rapid collapse into black holes rather than stable Thorne-Zytkow objects.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the grey two-moment (M1) neutrino transport scheme combined with the α-chain nuclear network and the chosen progenitor models fully capture the relevant physics without missing effects such as magnetic fields or more detailed neutrino interactions that could enable outflows.","pith_extraction_headline":"Simulations show neutron stars in massive stellar envelopes accrete rapidly and collapse to black holes rather than forming stable Thorne-Zytkow objects."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.23503/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"ai_meta_artifact","ran_at":"2026-05-21T08:39:39.713962Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T23:04:18.411719Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"36906687d997f74632f5e71facfd998cf40a9fd32b826c8c8d33880020c10b01"},"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"}