Hα Observations of SS Cyg at Quiescence and Outburst

Observations of Hα line of SS Cyg at quiescence and outburst are presented. The corresponding radial velocity curve is sinusoidal with semiamplitude K1=91±3.5 km/s. The width and intensity of the Hα line during quiescence are slightly variable. Its profile shape changes quite irregular but does not show the typical double-peaked structure of an accretion disk. The small peaks at the profile cores form S-wave with half-orbital period. The Hα profiles of SS Cyg at outburst consist of central emission core superposed on wide shallow absorption base. The intensity of the emission core is almost the same as that of the emission line in quiescence. The double-peaked shape of the profile is not well pronounced during the outburst too. On the base of the parameters of the Hα profile we estimate that the condition for the existence of an accretion disk during quiescence is not fulfilled. Such a structure can exist in outburst but it cannot be a dominant source of the Hα emission. Taking into account similarity of SS Cyg and the polar AM Her we conclude that the Balmer emission of SS Cyg originates mostly from the polar caps.