The variable light curve of the eclipsing symbiotic star AR Pavonis

Photometric measurements in four colours and visual observations of the eclipsing symbiotic star AR Pav covering almost 7 cycles of the 604.5 day orbit between 1982 and 1993 are presented. Together with published data they us allow to determine improved orbital ephemeries. The shape of the eclipse is analysed. Its width is found to be shorter than previously estimated. The brightness and colour changes during the orbital cycle are discussed. AR Pav is found to be highly variable out of eclipse. In some cycles a marked peak appears which is absent in others. Several explanations for the out-of-eclipse variability are suggested, the most satisfying of which is a brightness modulation due to variation in the mass transfer rate from the red giant to the hot component.