{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2009:23B7MKD7DSFB6TLUIFUUS45D44","short_pith_number":"pith:23B7MKD7","canonical_record":{"source":{"id":"0908.4026","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2009-08-27T15:00:22Z","cross_cats_sorted":[],"title_canon_sha256":"9d6293b67bce63ea8afe61cf24572ecf75df623d4d64b7aa995645d2863479b5","abstract_canon_sha256":"ace5e0327a0b64a2b84fe494bf06fa05483e0b022e1758b4d5d55212713fb71b"},"schema_version":"1.0"},"canonical_sha256":"d6c3f6287f1c8a1f4d7441694973a3e73659abb122ebd618682bf50e22e6dc90","source":{"kind":"arxiv","id":"0908.4026","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0908.4026","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"arxiv_version","alias_value":"0908.4026v3","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0908.4026","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"pith_short_12","alias_value":"23B7MKD7DSFB","created_at":"2026-05-18T12:25:58Z"},{"alias_kind":"pith_short_16","alias_value":"23B7MKD7DSFB6TLU","created_at":"2026-05-18T12:25:58Z"},{"alias_kind":"pith_short_8","alias_value":"23B7MKD7","created_at":"2026-05-18T12:25:58Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2009:23B7MKD7DSFB6TLUIFUUS45D44","target":"record","payload":{"canonical_record":{"source":{"id":"0908.4026","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2009-08-27T15:00:22Z","cross_cats_sorted":[],"title_canon_sha256":"9d6293b67bce63ea8afe61cf24572ecf75df623d4d64b7aa995645d2863479b5","abstract_canon_sha256":"ace5e0327a0b64a2b84fe494bf06fa05483e0b022e1758b4d5d55212713fb71b"},"schema_version":"1.0"},"canonical_sha256":"d6c3f6287f1c8a1f4d7441694973a3e73659abb122ebd618682bf50e22e6dc90","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:12:22.106626Z","signature_b64":"DS0Bph5JjJOyvYMAtwa4OsOKF447s9e9TVqkDj1fbFZq+suVpmyVvU29TuHTpKB+udDXfrJeZ/QkyohUax+JAg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"d6c3f6287f1c8a1f4d7441694973a3e73659abb122ebd618682bf50e22e6dc90","last_reissued_at":"2026-05-18T02:12:22.106041Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:12:22.106041Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"0908.4026","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:12:22Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"GwsOHiw7PpnR0FUoL4p7MuL+mvKodg5Afh50vBQruihSuVGAIWXPq8ZFN8huOmx7UN1TytGGbz5dZfC6FCKXCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T18:28:00.858605Z"},"content_sha256":"eba1c17561d28725f4bbb157c4675a379a9620bb70d43735de196b7bffc59ac6","schema_version":"1.0","event_id":"sha256:eba1c17561d28725f4bbb157c4675a379a9620bb70d43735de196b7bffc59ac6"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2009:23B7MKD7DSFB6TLUIFUUS45D44","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"Alan T. Tokunaga, Chihiro Tokoku, Chikako Yasui, Masao Saito, Naoto Kobayashi","submitted_at":"2009-08-27T15:00:22Z","abstract_excerpt":"The extreme outer Galaxy (EOG), the region with a Galactic radius of more than 18 kpc, is known to have very low metallicity, about one-tenth that of the solar neighborhood. We obtained deep near-infrared (NIR) images of two very young ($\\sim$0.5 Myr) star-forming clusters that are one of the most distant embedded clusters in the EOG. We find that in both clusters the fraction of stars with NIR excess, which originates from the circumstellar dust disk at radii of $\\leq$0.1 AU, is significantly lower than those in the solar neighborhood. Our results suggest that most stars forming in the low-me"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0908.4026","kind":"arxiv","version":3},"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":"2026-05-18T02:12:22Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"FYo671bP3gHBjtUhGekKYet+UlTo/1u8RJCbKbM1PM8EZ5XjwxEyIwRNadzt5jGd6yJo3ocNSVoaWLM34mnyCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T18:28:00.859326Z"},"content_sha256":"47d77448805ad4b57ba2a4d1a4c78fe3b72eb78812b72080ef0a2bbaf1df7888","schema_version":"1.0","event_id":"sha256:47d77448805ad4b57ba2a4d1a4c78fe3b72eb78812b72080ef0a2bbaf1df7888"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/23B7MKD7DSFB6TLUIFUUS45D44/bundle.json","state_url":"https://pith.science/pith/23B7MKD7DSFB6TLUIFUUS45D44/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/23B7MKD7DSFB6TLUIFUUS45D44/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":"2026-05-27T18:28:00Z","links":{"resolver":"https://pith.science/pith/23B7MKD7DSFB6TLUIFUUS45D44","bundle":"https://pith.science/pith/23B7MKD7DSFB6TLUIFUUS45D44/bundle.json","state":"https://pith.science/pith/23B7MKD7DSFB6TLUIFUUS45D44/state.json","well_known_bundle":"https://pith.science/.well-known/pith/23B7MKD7DSFB6TLUIFUUS45D44/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2009:23B7MKD7DSFB6TLUIFUUS45D44","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":"ace5e0327a0b64a2b84fe494bf06fa05483e0b022e1758b4d5d55212713fb71b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2009-08-27T15:00:22Z","title_canon_sha256":"9d6293b67bce63ea8afe61cf24572ecf75df623d4d64b7aa995645d2863479b5"},"schema_version":"1.0","source":{"id":"0908.4026","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0908.4026","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"arxiv_version","alias_value":"0908.4026v3","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0908.4026","created_at":"2026-05-18T02:12:22Z"},{"alias_kind":"pith_short_12","alias_value":"23B7MKD7DSFB","created_at":"2026-05-18T12:25:58Z"},{"alias_kind":"pith_short_16","alias_value":"23B7MKD7DSFB6TLU","created_at":"2026-05-18T12:25:58Z"},{"alias_kind":"pith_short_8","alias_value":"23B7MKD7","created_at":"2026-05-18T12:25:58Z"}],"graph_snapshots":[{"event_id":"sha256:47d77448805ad4b57ba2a4d1a4c78fe3b72eb78812b72080ef0a2bbaf1df7888","target":"graph","created_at":"2026-05-18T02:12:22Z","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":"The extreme outer Galaxy (EOG), the region with a Galactic radius of more than 18 kpc, is known to have very low metallicity, about one-tenth that of the solar neighborhood. We obtained deep near-infrared (NIR) images of two very young ($\\sim$0.5 Myr) star-forming clusters that are one of the most distant embedded clusters in the EOG. We find that in both clusters the fraction of stars with NIR excess, which originates from the circumstellar dust disk at radii of $\\leq$0.1 AU, is significantly lower than those in the solar neighborhood. Our results suggest that most stars forming in the low-me","authors_text":"Alan T. Tokunaga, Chihiro Tokoku, Chikako Yasui, Masao Saito, Naoto Kobayashi","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2009-08-27T15:00:22Z","title":"The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0908.4026","kind":"arxiv","version":3},"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:eba1c17561d28725f4bbb157c4675a379a9620bb70d43735de196b7bffc59ac6","target":"record","created_at":"2026-05-18T02:12:22Z","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":"ace5e0327a0b64a2b84fe494bf06fa05483e0b022e1758b4d5d55212713fb71b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2009-08-27T15:00:22Z","title_canon_sha256":"9d6293b67bce63ea8afe61cf24572ecf75df623d4d64b7aa995645d2863479b5"},"schema_version":"1.0","source":{"id":"0908.4026","kind":"arxiv","version":3}},"canonical_sha256":"d6c3f6287f1c8a1f4d7441694973a3e73659abb122ebd618682bf50e22e6dc90","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"d6c3f6287f1c8a1f4d7441694973a3e73659abb122ebd618682bf50e22e6dc90","first_computed_at":"2026-05-18T02:12:22.106041Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:12:22.106041Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"DS0Bph5JjJOyvYMAtwa4OsOKF447s9e9TVqkDj1fbFZq+suVpmyVvU29TuHTpKB+udDXfrJeZ/QkyohUax+JAg==","signature_status":"signed_v1","signed_at":"2026-05-18T02:12:22.106626Z","signed_message":"canonical_sha256_bytes"},"source_id":"0908.4026","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:eba1c17561d28725f4bbb157c4675a379a9620bb70d43735de196b7bffc59ac6","sha256:47d77448805ad4b57ba2a4d1a4c78fe3b72eb78812b72080ef0a2bbaf1df7888"],"state_sha256":"e123b7b36cfc8d91037b1a28337a11df824d5fc78b8e7e12dca530a3bbc618bf"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"O2HkZeD1vkXJpTcJp5xP3ApLqiZsj76i6cmv24dzFO3PlohOicsAOk3pKPteJZFQPz1eowLNVJrXLAnE7hmwCQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-27T18:28:00.863143Z","bundle_sha256":"d883a77243d4112eb043324aeaca551844148cb42fdbcbe7cd3321c2fd0e03bc"}}