Spiral Structure in WZ Sagittae around the 2001 Outburst Maximum

Abstract

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 Å, 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 of an outburst and may be present in all SU UMa stars.

5 pages, 8 figures, accepted for publication in PASJ

References in corpus (1)

• Evolution of spiral shocks in U Gem during outburst

Cited by in corpus (27)

• The 2001 Superoutburst of WZ Sagittae
• Variable Star Network: World Center for Transient Object Astronomy and Variable Stars
• WZ Sge-Type Dwarf Novae
• Is evidence for enhanced mass transfer during dwarf-nova outbursts well substantiated?
• On the Origin of Early Superhumps in WZ Sge-Type Stars
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. III: The Third Year (2010--2011)
• A 6.3-h superhump in the cataclysmic variable TV Columbae: the longest yet seen
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VII: The Seventh Year (2014-2015)
• The accretion disk in the post period-minimum cataclysmic variable SDSS J080434.20+510349.2
• SDSS J123813.73-033933.0, a cataclysmic variable evolved beyond the period minimum
• The helium-rich cataclysmic variable SBSS 1108+574
• Time-resolved observations of the short period CV SDSS J123813.73-033933.0
• Spin-resolved spectroscopy of the intermediate polar DQ Her
• Spectroscopic Observations of the WZ Sge-Type Dwarf Nova GW Librae during the 2007 Superoutburst
• Dramatic Spectral Evolution of WZ Sagittae during the 2001 Superoutburst
• WZ Sge-Type Star V592 Herculis
• Spectroscopic and Photometric Observations of Dwarf Nova Superoutbursts by the 3.8 m Telescope Seimei and the Variable Star Network
• Doppler tomography of Cataclysmic Variables
• On the Nature of Long-Period Dwarf Novae with Rare and Low-Amplitude Outbursts
• Analysis of spiral structure in the accretion disc of the novalike Cataclysmic Variable EC21178--5417
• On the orbital period of the cataclysmic variable V592 Herculis
• Spectroscopic Observations of V455 Andromedae Superoutburst in 2007: the Most Exotic Spectral Features in Dwarf Nova Outbursts
• A systematic study of spiral density waves in the accretion discs of Cataclysmic Variables
• A spectroscopic analysis of the eclipsing nova-like EC21178-5417 -- discovery of spiral density structures
• PNV J00444033+4113068: early superhumps with 0.7 mag amplitude and non-red color
• On the Colour Variations of Negative Superhumps
• Is KT Mon a Classical Nova?