{"paper":{"title":"Chemical Evolution of the Circumstellar Envelopes of Carbon-rich Post-AGB objects","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"F. Herpin, J. Cernicharo, J.R. Goicoechea, J.R. Pardo","submitted_at":"2002-06-11T10:28:59Z","abstract_excerpt":"We have observed with the 30-m IRAM telescope, the CSO telescope and the ISOsatellite (Infrared Space Observatory) the rotational lines of CO at millimeter, submillimeter and far infrared wavelengths in the direction of C-rich stellar objects at different stages of evolution : CRL 2688 (a very young Proto-Planetary Nebula), CRL 618 (a Proto-Planetary Nebula), and NGC 7027 (a young Planetary Nebula). Several changes in the longwave emission of CO and other molecules are discussed here in relation with the degree of evolution of the objects. In the early stages, represented by CRL 2688, the long"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0206167","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/astro-ph/0206167/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}