The 2001 superoutburst of WZ Sge: Is there any connection with Nova Outbursts?

摘要

We have observed WZ Sge with high resolution echelle spectroscopy during the 2001 superoutburst. The hot-spot arising near the secondary star is again visible 15 day after its first detection. We have been able to measure its position as a function of orbital phase directly from individual spectra. We derive a a semiamplitude of K_(hs) = 457 ± 16km s~(-1) and a systemic velocity of γ = 0 ± 14km s~(-1). We also show that the accretion disc has an ellipsoidal shape with a value around e = 0.75. Based on these facts we derive a phase shift of ΔΦ = -0.12 between the eclipse and the inferior conjuntion ephemeris. If this is the case, then the hot-spot appears located at the trailing side of the red dwarf and must be the result of in-falling material back to the donor star.