{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2008:LWLOJLU7UUOUCPJWSS7DGMONFG","short_pith_number":"pith:LWLOJLU7","canonical_record":{"source":{"id":"0810.0281","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph","submitted_at":"2008-10-01T20:23:24Z","cross_cats_sorted":[],"title_canon_sha256":"d245801005a5ef34557d859a08a139817246493cde072f6b11e0ec186d37a4ee","abstract_canon_sha256":"0c1c9074deef1b61606ce99529112dafa5b572ab7cd4b48a716f46369a99b95e"},"schema_version":"1.0"},"canonical_sha256":"5d96e4ae9fa51d413d3694be3331cd298aee9cb0eeebc66839d6f4d2f1ae5afb","source":{"kind":"arxiv","id":"0810.0281","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0810.0281","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"arxiv_version","alias_value":"0810.0281v1","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0810.0281","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"pith_short_12","alias_value":"LWLOJLU7UUOU","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_16","alias_value":"LWLOJLU7UUOUCPJW","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_8","alias_value":"LWLOJLU7","created_at":"2026-05-18T12:25:57Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2008:LWLOJLU7UUOUCPJWSS7DGMONFG","target":"record","payload":{"canonical_record":{"source":{"id":"0810.0281","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph","submitted_at":"2008-10-01T20:23:24Z","cross_cats_sorted":[],"title_canon_sha256":"d245801005a5ef34557d859a08a139817246493cde072f6b11e0ec186d37a4ee","abstract_canon_sha256":"0c1c9074deef1b61606ce99529112dafa5b572ab7cd4b48a716f46369a99b95e"},"schema_version":"1.0"},"canonical_sha256":"5d96e4ae9fa51d413d3694be3331cd298aee9cb0eeebc66839d6f4d2f1ae5afb","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:15:33.072745Z","signature_b64":"Qxc87SZCdvkxEin1GLhE8uZrD/jxps+z1wlqslxIrSxJ86/S5ETb+FpFKCKYwQ9gIHXkyltlIsQRqa5Tha9WBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"5d96e4ae9fa51d413d3694be3331cd298aee9cb0eeebc66839d6f4d2f1ae5afb","last_reissued_at":"2026-05-18T02:15:33.071943Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:15:33.071943Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"0810.0281","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:15:33Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"JSQ70B054tc+hvS3N0zegeH6qHiSEquVFw6UwHdFPIyGinZdfypp6KDtdOoDYFTpQImX2ZD7VkgxS8x3dKIsAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-17T20:19:51.281198Z"},"content_sha256":"01b468d3da3d4a984a850da89acbb8c97df0ebd28a83451a012284d8e9a94731","schema_version":"1.0","event_id":"sha256:01b468d3da3d4a984a850da89acbb8c97df0ebd28a83451a012284d8e9a94731"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2008:LWLOJLU7UUOUCPJWSS7DGMONFG","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"C. Akerman, D. Fabbian, M. Asplund, M. Pettini, P. E. Nissen","submitted_at":"2008-10-01T20:23:24Z","abstract_excerpt":"We present new measurements of the abundances of carbon and oxygen derived from high-excitation C I and O I absorption lines in metal-poor halo stars, with the aim of clarifying the main sources of these two elements in the early stages of the chemical enrichment of the Galaxy. We target 15 new stars compared to our previous study, with an emphasis on additional C/O determinations in the crucial metallicity range -3<[Fe/H]<-2. Departures from local thermodynamic equilibrium were accounted for in the line formation for both carbon and oxygen. The non-LTE effects are very strong at the lowest me"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0810.0281","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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:15:33Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ZKrHRLL2gjx1aBu8RYo24H735u9lePsR7BZ0CI14KcHMCF+F5nzsTtUdeTpZXAV7InhEsWtqGYhkt8Sbf0VJCQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-17T20:19:51.282048Z"},"content_sha256":"487f74cfda383e53e140006a7a2539c1d92ece3a16a6d346dacf4f2757263709","schema_version":"1.0","event_id":"sha256:487f74cfda383e53e140006a7a2539c1d92ece3a16a6d346dacf4f2757263709"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/bundle.json","state_url":"https://pith.science/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-17T20:19:51Z","links":{"resolver":"https://pith.science/pith/LWLOJLU7UUOUCPJWSS7DGMONFG","bundle":"https://pith.science/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/bundle.json","state":"https://pith.science/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/state.json","well_known_bundle":"https://pith.science/.well-known/pith/LWLOJLU7UUOUCPJWSS7DGMONFG/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2008:LWLOJLU7UUOUCPJWSS7DGMONFG","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"0c1c9074deef1b61606ce99529112dafa5b572ab7cd4b48a716f46369a99b95e","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph","submitted_at":"2008-10-01T20:23:24Z","title_canon_sha256":"d245801005a5ef34557d859a08a139817246493cde072f6b11e0ec186d37a4ee"},"schema_version":"1.0","source":{"id":"0810.0281","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0810.0281","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"arxiv_version","alias_value":"0810.0281v1","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0810.0281","created_at":"2026-05-18T02:15:33Z"},{"alias_kind":"pith_short_12","alias_value":"LWLOJLU7UUOU","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_16","alias_value":"LWLOJLU7UUOUCPJW","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_8","alias_value":"LWLOJLU7","created_at":"2026-05-18T12:25:57Z"}],"graph_snapshots":[{"event_id":"sha256:487f74cfda383e53e140006a7a2539c1d92ece3a16a6d346dacf4f2757263709","target":"graph","created_at":"2026-05-18T02:15:33Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"We present new measurements of the abundances of carbon and oxygen derived from high-excitation C I and O I absorption lines in metal-poor halo stars, with the aim of clarifying the main sources of these two elements in the early stages of the chemical enrichment of the Galaxy. We target 15 new stars compared to our previous study, with an emphasis on additional C/O determinations in the crucial metallicity range -3<[Fe/H]<-2. Departures from local thermodynamic equilibrium were accounted for in the line formation for both carbon and oxygen. The non-LTE effects are very strong at the lowest me","authors_text":"C. Akerman, D. Fabbian, M. Asplund, M. Pettini, P. E. Nissen","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph","submitted_at":"2008-10-01T20:23:24Z","title":"The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0810.0281","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:01b468d3da3d4a984a850da89acbb8c97df0ebd28a83451a012284d8e9a94731","target":"record","created_at":"2026-05-18T02:15:33Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"0c1c9074deef1b61606ce99529112dafa5b572ab7cd4b48a716f46369a99b95e","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph","submitted_at":"2008-10-01T20:23:24Z","title_canon_sha256":"d245801005a5ef34557d859a08a139817246493cde072f6b11e0ec186d37a4ee"},"schema_version":"1.0","source":{"id":"0810.0281","kind":"arxiv","version":1}},"canonical_sha256":"5d96e4ae9fa51d413d3694be3331cd298aee9cb0eeebc66839d6f4d2f1ae5afb","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5d96e4ae9fa51d413d3694be3331cd298aee9cb0eeebc66839d6f4d2f1ae5afb","first_computed_at":"2026-05-18T02:15:33.071943Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:15:33.071943Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"Qxc87SZCdvkxEin1GLhE8uZrD/jxps+z1wlqslxIrSxJ86/S5ETb+FpFKCKYwQ9gIHXkyltlIsQRqa5Tha9WBA==","signature_status":"signed_v1","signed_at":"2026-05-18T02:15:33.072745Z","signed_message":"canonical_sha256_bytes"},"source_id":"0810.0281","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:01b468d3da3d4a984a850da89acbb8c97df0ebd28a83451a012284d8e9a94731","sha256:487f74cfda383e53e140006a7a2539c1d92ece3a16a6d346dacf4f2757263709"],"state_sha256":"560113e42dfb32f37c423db05f80611c0eb2cd4727bd5668ed709fa6994bd368"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"rVDwWnYYgtyir5/Q+lZtwij7rEM+tKUpzsnBIIx/FPwQ7uEwetjR7lg3yUULzIctB1VWLpm62Q+LaWcmbeFGCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-17T20:19:51.295211Z","bundle_sha256":"19cff99ba7b416f4abe0763ab53106d041cb89459dc66b230674966c6030d81d"}}