{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2003:6LCNIUFCJDCRDIK723LWYFARXJ","short_pith_number":"pith:6LCNIUFC","schema_version":"1.0","canonical_sha256":"f2c4d450a248c511a15fd6d76c1411ba54f1a8340a270164eaa365ebf6a22d7e","source":{"kind":"arxiv","id":"astro-ph/0302564","version":1},"attestation_state":"computed","paper":{"title":"High NH2D/NH3 ratios in protostellar cores","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"Jennifer Hatchell","submitted_at":"2003-02-27T10:05:20Z","abstract_excerpt":"Observations of low mass protostars which probe small enough size scales to be within likely CO depletion regions show the highest [NH2D]/[NH3] ratios yet measured, of 4--33%. These molecular D/H ratios are higher than those measured on larger scales, showing that deuterium fractionation increases towards protostellar cores. As in cold clouds, such high ratios can be produced by gas-phase ion-molecule chemistry in the presence of depletion. Grain surface chemistry is less likely to explain the deuterium enhancement, as it would require higher fractionation in ices than current models predict. "},"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":"astro-ph/0302564","kind":"arxiv","version":1},"metadata":{"license":"","primary_cat":"astro-ph","submitted_at":"2003-02-27T10:05:20Z","cross_cats_sorted":[],"title_canon_sha256":"409960c34b28d15bfc174e6721f7fe75999c48ad97157e1f346c3bb76273fc65","abstract_canon_sha256":"feaea9c3ee756eaa1a10e79fc138fe7f18bf717c436f132bf3281dd5e02ef791"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T04:21:41.709169Z","signature_b64":"cEUwCOqs52KpBBKw+QH2Msxn5ztAZfb37QQYs42iX0XwdTJhaOjON45xdOvs1/WCv9/+y0QWBz2DTx3O6NsZBQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"f2c4d450a248c511a15fd6d76c1411ba54f1a8340a270164eaa365ebf6a22d7e","last_reissued_at":"2026-05-18T04:21:41.708527Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T04:21:41.708527Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"High NH2D/NH3 ratios in protostellar cores","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"Jennifer Hatchell","submitted_at":"2003-02-27T10:05:20Z","abstract_excerpt":"Observations of low mass protostars which probe small enough size scales to be within likely CO depletion regions show the highest [NH2D]/[NH3] ratios yet measured, of 4--33%. These molecular D/H ratios are higher than those measured on larger scales, showing that deuterium fractionation increases towards protostellar cores. As in cold clouds, such high ratios can be produced by gas-phase ion-molecule chemistry in the presence of depletion. Grain surface chemistry is less likely to explain the deuterium enhancement, as it would require higher fractionation in ices than current models predict. "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0302564","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"},"aliases":[{"alias_kind":"arxiv","alias_value":"astro-ph/0302564","created_at":"2026-05-18T04:21:41.708625+00:00"},{"alias_kind":"arxiv_version","alias_value":"astro-ph/0302564v1","created_at":"2026-05-18T04:21:41.708625+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.astro-ph/0302564","created_at":"2026-05-18T04:21:41.708625+00:00"},{"alias_kind":"pith_short_12","alias_value":"6LCNIUFCJDCR","created_at":"2026-05-18T12:25:51.375804+00:00"},{"alias_kind":"pith_short_16","alias_value":"6LCNIUFCJDCRDIK7","created_at":"2026-05-18T12:25:51.375804+00:00"},{"alias_kind":"pith_short_8","alias_value":"6LCNIUFC","created_at":"2026-05-18T12:25:51.375804+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/6LCNIUFCJDCRDIK723LWYFARXJ","json":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ.json","graph_json":"https://pith.science/api/pith-number/6LCNIUFCJDCRDIK723LWYFARXJ/graph.json","events_json":"https://pith.science/api/pith-number/6LCNIUFCJDCRDIK723LWYFARXJ/events.json","paper":"https://pith.science/paper/6LCNIUFC"},"agent_actions":{"view_html":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ","download_json":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ.json","view_paper":"https://pith.science/paper/6LCNIUFC","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=astro-ph/0302564&json=true","fetch_graph":"https://pith.science/api/pith-number/6LCNIUFCJDCRDIK723LWYFARXJ/graph.json","fetch_events":"https://pith.science/api/pith-number/6LCNIUFCJDCRDIK723LWYFARXJ/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ/action/timestamp_anchor","attest_storage":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ/action/storage_attestation","attest_author":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ/action/author_attestation","sign_citation":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ/action/citation_signature","submit_replication":"https://pith.science/pith/6LCNIUFCJDCRDIK723LWYFARXJ/action/replication_record"}},"created_at":"2026-05-18T04:21:41.708625+00:00","updated_at":"2026-05-18T04:21:41.708625+00:00"}