{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2009:RK7YD6BXDWWLQX7FNFMQG3OWBP","short_pith_number":"pith:RK7YD6BX","schema_version":"1.0","canonical_sha256":"8abf81f8371dacb85fe56959036dd60bc63cef107571daf340960b905c18e1ae","source":{"kind":"arxiv","id":"0909.2652","version":2},"attestation_state":"computed","paper":{"title":"Forming Planetesimals in Solar and Extrasolar Nebulae","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.EP","authors_text":"A. Youdin (CITA), E. Chiang (UC Berkeley)","submitted_at":"2009-09-14T20:12:00Z","abstract_excerpt":"Planets are built from planetesimals: solids larger than a kilometer which grow by colliding pairwise. Planetesimals themselves are unlikely to form by two-body collisions; sub-km objects have gravitational fields individually too weak, and electrostatic attraction is too feeble for growth beyond a few cm. We review the possibility that planetesimals form when self-gravity brings together vast ensembles of small particles. Even when self-gravity is weak, aerodynamic processes can accumulate solids relative to gas, paving the way for gravitational collapse. Particles pile up as they drift radia"},"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":"0909.2652","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.EP","submitted_at":"2009-09-14T20:12:00Z","cross_cats_sorted":["astro-ph.SR"],"title_canon_sha256":"3d2601484181c5c29a64682ed638cbf8cae479143aa206473a58e1b3390e5d3a","abstract_canon_sha256":"ccabdaf2d0d811ffeb0f6b12c6f76433c91507c96f3eaa6e0cd280dd458965a6"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:11:47.931023Z","signature_b64":"dmSUxDFVhW7T0zReUvaDGNXEiPmKz5rDw2QUXWnw+hIseO//b9qXsJTCN9DyTg7+rJZcVmJQ+jp1KjTM5RWeBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"8abf81f8371dacb85fe56959036dd60bc63cef107571daf340960b905c18e1ae","last_reissued_at":"2026-05-18T02:11:47.930351Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:11:47.930351Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Forming Planetesimals in Solar and Extrasolar Nebulae","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.EP","authors_text":"A. Youdin (CITA), E. Chiang (UC Berkeley)","submitted_at":"2009-09-14T20:12:00Z","abstract_excerpt":"Planets are built from planetesimals: solids larger than a kilometer which grow by colliding pairwise. Planetesimals themselves are unlikely to form by two-body collisions; sub-km objects have gravitational fields individually too weak, and electrostatic attraction is too feeble for growth beyond a few cm. We review the possibility that planetesimals form when self-gravity brings together vast ensembles of small particles. Even when self-gravity is weak, aerodynamic processes can accumulate solids relative to gas, paving the way for gravitational collapse. Particles pile up as they drift radia"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0909.2652","kind":"arxiv","version":2},"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"},"aliases":[{"alias_kind":"arxiv","alias_value":"0909.2652","created_at":"2026-05-18T02:11:47.930438+00:00"},{"alias_kind":"arxiv_version","alias_value":"0909.2652v2","created_at":"2026-05-18T02:11:47.930438+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0909.2652","created_at":"2026-05-18T02:11:47.930438+00:00"},{"alias_kind":"pith_short_12","alias_value":"RK7YD6BXDWWL","created_at":"2026-05-18T12:26:01.383474+00:00"},{"alias_kind":"pith_short_16","alias_value":"RK7YD6BXDWWLQX7F","created_at":"2026-05-18T12:26:01.383474+00:00"},{"alias_kind":"pith_short_8","alias_value":"RK7YD6BX","created_at":"2026-05-18T12:26:01.383474+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP","json":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP.json","graph_json":"https://pith.science/api/pith-number/RK7YD6BXDWWLQX7FNFMQG3OWBP/graph.json","events_json":"https://pith.science/api/pith-number/RK7YD6BXDWWLQX7FNFMQG3OWBP/events.json","paper":"https://pith.science/paper/RK7YD6BX"},"agent_actions":{"view_html":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP","download_json":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP.json","view_paper":"https://pith.science/paper/RK7YD6BX","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=0909.2652&json=true","fetch_graph":"https://pith.science/api/pith-number/RK7YD6BXDWWLQX7FNFMQG3OWBP/graph.json","fetch_events":"https://pith.science/api/pith-number/RK7YD6BXDWWLQX7FNFMQG3OWBP/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP/action/timestamp_anchor","attest_storage":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP/action/storage_attestation","attest_author":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP/action/author_attestation","sign_citation":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP/action/citation_signature","submit_replication":"https://pith.science/pith/RK7YD6BXDWWLQX7FNFMQG3OWBP/action/replication_record"}},"created_at":"2026-05-18T02:11:47.930438+00:00","updated_at":"2026-05-18T02:11:47.930438+00:00"}