{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:LQFIHX3ISNF4RIUROZVM46AKN4","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":"44d1cc20fc16dc75cdb476343b0e192c1bee8ce2eb5833e79bff211d41df2786","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2013-06-26T20:00:31Z","title_canon_sha256":"c20652c8c191bf66581ba2195b9c2f12daf6ded7eba0c81609376cd46c2d4793"},"schema_version":"1.0","source":{"id":"1306.6339","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1306.6339","created_at":"2026-05-18T01:49:07Z"},{"alias_kind":"arxiv_version","alias_value":"1306.6339v1","created_at":"2026-05-18T01:49:07Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1306.6339","created_at":"2026-05-18T01:49:07Z"},{"alias_kind":"pith_short_12","alias_value":"LQFIHX3ISNF4","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_16","alias_value":"LQFIHX3ISNF4RIUR","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_8","alias_value":"LQFIHX3I","created_at":"2026-05-18T12:27:51Z"}],"graph_snapshots":[{"event_id":"sha256:fe796d7f1b8184083cbe86be19db1799c1528ac65a9b2b12f090b90cd026c1fd","target":"graph","created_at":"2026-05-18T01:49:07Z","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 a deep Cousins RI photometric survey of the open cluster NGC 1960, complete to R_C \\simeq 22, I_C \\simeq 21, that is used to select a sample of very low-mass cluster candidates. Gemini spectroscopy of a subset of these is used to confirm membership and locate the age-dependent \"lithium depletion boundary\" (LDB) --the luminosity at which lithium remains unburned in its low-mass stars. The LDB implies a cluster age of 22 +/-4 Myr and is quite insensitive to choice of evolutionary model. NGC 1960 is the youngest cluster for which a LDB age has been estimated and possesses a well popula","authors_text":"(2) University of Exeter, (3) University of Sheffield), Cameron P.M. Bell (2), N.J. Mayne (2), R.D. Jeffries (1), S.P. Littlefair (3) ((1) Keele University, Tim Naylor (2)","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2013-06-26T20:00:31Z","title":"A lithium depletion boundary age of 22 Myr for NGC 1960"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1306.6339","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":"sha256:3b9b7f1292d1ac1c2d09cdb1ab06d79f7e4394f7c45f4aa80d497e277683c9c1","target":"record","created_at":"2026-05-18T01:49:07Z","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":"44d1cc20fc16dc75cdb476343b0e192c1bee8ce2eb5833e79bff211d41df2786","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2013-06-26T20:00:31Z","title_canon_sha256":"c20652c8c191bf66581ba2195b9c2f12daf6ded7eba0c81609376cd46c2d4793"},"schema_version":"1.0","source":{"id":"1306.6339","kind":"arxiv","version":1}},"canonical_sha256":"5c0a83df68934bc8a291766ace780a6f33c376bba0e5faf58f07a87eac1894e6","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5c0a83df68934bc8a291766ace780a6f33c376bba0e5faf58f07a87eac1894e6","first_computed_at":"2026-05-18T01:49:07.415351Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:49:07.415351Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"8JqNuK7ZbpZpsfNedNoLGc1hUMP3NnVs3Qe0p9As8RvWNQjdJ9QE90OZOv58DYdq2oWEY4I4xGdaZF1o8y2fAA==","signature_status":"signed_v1","signed_at":"2026-05-18T01:49:07.415963Z","signed_message":"canonical_sha256_bytes"},"source_id":"1306.6339","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:3b9b7f1292d1ac1c2d09cdb1ab06d79f7e4394f7c45f4aa80d497e277683c9c1","sha256:fe796d7f1b8184083cbe86be19db1799c1528ac65a9b2b12f090b90cd026c1fd"],"state_sha256":"a092971ad85d663c07b3ae849a7674f6a37887bbd5312db1baedf4158c0c9d10"}