The eclipsing binary star RZ Cas: accretion-driven variability of the multimode oscillation spectrum

We analysed photometric time series of the active, semidetached Algol-type system RZ Cas obtained in 1999-2009, in order to search for seasonal and short-term variations in the oscillation spectrum of RZ Cas A. The orbital period shows ±1 s cyclic variations on time-scales of 6-9 years. We detected six low-degree p-mode oscillations with periods between 22.3 and 26.22 min and obtained safe mode identifications using the periodic spatial filter method. The amplitudes and frequencies of all modes vary.