Investigating the structure of the accretion disc in WZ Sge from multiwaveband time-resolved spectroscopic observations – II |
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| Authors: | Elena Mason Warren Skidmore Steve B Howell David R Ciardi Stuart Littlefair V S Dhillon |
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| Institution: | Department of Physics and Astronomy, University of Wyoming, PO Box 3905, University Station, Laramie, WY 82071, USA;Astrophysics Group, Planetary Science Institute, 620 N. 6th Avenue, Tucson, AZ 85705, USA;School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS;Department of Astronomy, 211 Bryant Space Science Center, PO Box 112055, University of Florida, Gainesville, FL 32611, USA;Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH |
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| Abstract: | We present our second paper describing multiwaveband time-resolved spectroscopy of WZ Sge. We analyse the evolution of both optical and IR emission lines throughout the orbital period and find evidence, in the Balmer lines, for an optically thin accretion disc and an optically thick hotspot. Optical and IR emission lines are used to compute radial velocity curves. Fits to our radial velocity measurements give an internally inconsistent set of values for K 1, γ and the phase of red-to-blue crossing. We present a probable explanation for these discrepancies, and provide evidence for similar behaviour in other short orbital period dwarf novae. Selected optical and IR spectra are measured to determine the accretion disc radii. Values for the disc radii are found to be strongly dependent on the assumed WD mass and binary orbital inclination. However, the separation of the peaks in the optical emission line (i.e., an indication of the outer disc radius) has been found to be constant during all phases of the supercycle period over the last 40 years. |
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| Keywords: | accretion accretion discs binaries: close stars: individual: WZ Sge novae cataclysmic variables |
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