{"paper":{"title":"Spiral Structure in WZ Sagittae around the 2001 Outburst Maximum","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"Daisaku Nogami, Hajime Baba, Katsura Matsumoto, Kazuya Ayani, Kozo Sadakane, Makoto Makita, Masayuki Ioroi, Taichi Kato, Yuji Norimoto","submitted_at":"2001-12-16T07:30:04Z","abstract_excerpt":"Intermediate resolution phase-resolved spectra of WZ Sge were obtained on five consecutive nights (July 23 -- 27) covering the initial stage of the 2001 superoutburst. Double-peaked emission lines of He\\textsc{II} at 4686 \\AA, which were absent on July 23, emerged on July 24 together with emission lines of C\\textsc{III} / N\\textsc{III} Bowen blend. Analyses of the He\\textsc{II} emission lines using the Doppler tomography revealed an asymmetric spiral structure on the accretion disk. This finding demonstrates that spiral shocks with a very short orbital period can arise during the initial stage"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0112374","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"}