The four periodicities of the cataclysmic variable TV Columbae

Abstract

I present six nights of simultaneous optical photometry and spectroscopy aimed at observing the four periodicities of TV Col. The 32-min white dwarf spin period (known from the X-ray band) is not convincingly detected in the optical. The 5.5-h orbital period is manifest both photometrically and in the emission-line radial velocities. The emission lines show disc emission with a superimposed S-wave. Near orbital phase 0.8, the S-wave is at inferior conjunction, the photometric variation is at minimum, there is absorption in the line centres and we see X-ray dips. All these findings suggest that the rim of the disc is thickened at this location. The 4-d and 5.2-h cycles dominate the continuum variations but do not change the emission-line profiles. These modulations are not absolutely coherent