{"paper":{"title":"Identification of three new proto-Planetary Nebulae exhibiting the unidentified feature at 21 um","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"(2) Harvard-Smithsonian Center for Astrophysics, (3) INAF-Catania Astrophysical Observatory), A. Hart (2), C. Trigilio (3), G. Fazio (2) ((1) Max-Planck-Institut fuer Radioastronomie, G. Umana (3), J. L. Hora (2), L. Cerrigone (1)","submitted_at":"2011-06-29T18:18:29Z","abstract_excerpt":"Among its great findings, the IRAS mission showed the existence of an unidentified mid-IR feature around 21 um. Since its discovery, this feature has been detected in all C-rich proto-PNe of intermediate spectral type (A-G) and - weakly - in a few PNe and AGB stars, but the nature of its carriers remains unknown. In this paper, we show the detection of this feature in the spectra of three new stars transiting from the AGB to the PN stage obtained with the Spitzer Space Telescope. Following a recent suggestion, we try to model the SEDs of our targets with amorphous carbon and FeO, which might b"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1106.6018","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"}