{"paper":{"title":"Photometry and Spectroscopy of the Type IIP SN 1999em from Outburst to Dust Formation","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"A.Elmhamdi, A.Pastorello, E.Cappellaro, F.Patat, G.Altavilla, I.J.Danziger, M.Salvo, M.Turatto, N.Chugai, S.Benetti","submitted_at":"2002-09-30T15:36:59Z","abstract_excerpt":"We present photometry and spectra of the type IIP SN1999em in NGC 1637 from several days after the outburst till day 642. An amount of $\\approx 0.02 M_{\\odot}$ of ejected $^{56}$Ni is inferred using the recovered bolometric light curve . The H$\\alpha$ and He I 10830 \\AA lines at the nebular epoch show that the distribution of the bulk of $^{56}$Ni can be represented approximately by a sphere of $^{56}$Ni with a velocity of 1500 km s$^{-1}$, which is shifted towards the far hemisphere by about 400 km s$^{-1}$. The fine structure of the H$\\alpha$ at the photospheric epoch reminiscent of the \"Boc"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0209623","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"}