{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2009:EJNODK5AKDMKSWZCM2ZSHQGEYW","short_pith_number":"pith:EJNODK5A","schema_version":"1.0","canonical_sha256":"225ae1aba050d8a95b2266b323c0c4c5b9664415ab9f41a3d21c522757e08a49","source":{"kind":"arxiv","id":"0910.4496","version":1},"attestation_state":"computed","paper":{"title":"On the mass of the neutron star in Cyg X-2","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"G. Israelian, J. Casares, J.I. Gonzalez Hernandez, R. Rebolo","submitted_at":"2009-10-23T12:27:18Z","abstract_excerpt":"We present new high resolution spectroscopy of the low mass X-ray binary Cyg X-2 which enables us to refine the orbital solution and rotational broadening of the donor star. In contrast with Elebert et al (2009) we find a good agreement with results reported in Casares et al. (1998). We measure $P=9.84450\\pm0.00019$ day, $K_2=86.5\\pm1.2$ km s$^{-1}$ and $V \\sin i=33.7\\pm0.9$ km s$^{-1}$. These values imply $q=M_{2}/M_{1}=0.34 \\pm 0.02$ and $M_{1}=1.71\\pm 0.21$ M$_{\\odot}$ (for $i=62.5 \\pm 4^{\\circ}$). Therefore, the neutron star in Cyg X-2 can be more massive than canonical. We also find no ev"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"0910.4496","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2009-10-23T12:27:18Z","cross_cats_sorted":[],"title_canon_sha256":"ade2d7407bd137adf04ae21397b0c41776e6da627f15dd5ef3eb8beb91afca3b","abstract_canon_sha256":"e0768b13a902eafcbcf47b2aa450df4e250499e9b02dbe3cd370ca3fb500c4f4"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:11:12.206842Z","signature_b64":"EiUXjvzc5XB5j6hhjpiebcjghigQ3WmZFFN7wlQmWOO4cAWjrGPQNyIiSCANihg25CUUQouUbPlsVkRQzwzOCg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"225ae1aba050d8a95b2266b323c0c4c5b9664415ab9f41a3d21c522757e08a49","last_reissued_at":"2026-05-18T02:11:12.205896Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:11:12.205896Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"On the mass of the neutron star in Cyg X-2","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"G. Israelian, J. Casares, J.I. Gonzalez Hernandez, R. Rebolo","submitted_at":"2009-10-23T12:27:18Z","abstract_excerpt":"We present new high resolution spectroscopy of the low mass X-ray binary Cyg X-2 which enables us to refine the orbital solution and rotational broadening of the donor star. In contrast with Elebert et al (2009) we find a good agreement with results reported in Casares et al. (1998). We measure $P=9.84450\\pm0.00019$ day, $K_2=86.5\\pm1.2$ km s$^{-1}$ and $V \\sin i=33.7\\pm0.9$ km s$^{-1}$. These values imply $q=M_{2}/M_{1}=0.34 \\pm 0.02$ and $M_{1}=1.71\\pm 0.21$ M$_{\\odot}$ (for $i=62.5 \\pm 4^{\\circ}$). Therefore, the neutron star in Cyg X-2 can be more massive than canonical. 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