{"paper":{"title":"Nearby Supernova Factory Observations of SN 2006D: On Sporadic Carbon Signatures in Early Type Ia Supernova Spectra","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"A. Bauer, B. A. Weaver, C. Aragon, C. Baltay, C. Buton, D. Rabinowitz, E. Baron, E. Gangler, E. Pecontal, G. Aldering, G. Rigaudier, G. Smadja, J. Parrent, K. Runge, L. Wang, P. Antilogus, P. Nugent, R. Kessler, R. Pain, R. Pereira, R. Scalzo, S. Bailey, S. Bongard, S. Gilles, S. Loken, S. Perlmutter, The Nearby Supernova Factory: R. C. Thomas, Y. Copin","submitted_at":"2006-11-10T23:27:41Z","abstract_excerpt":"We present four spectra of the Type Ia supernova (SN Ia) 2006D extending from -7 to +13 days with respect to B-band maximum. The spectra include the strongest signature of unburned material at photospheric velocities observed in a SN Ia to date. The earliest spectrum exhibits C II absorption features below 14,000 km/s, including a distinctive C II \\lambda 6580 absorption feature. The carbon signatures dissipate as the SN approaches peak brightness. In addition to discussing implications of photospheric-velocity carbon for white dwarf explosion models, we outline some factors that may influence"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0611356","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"}