Long-term Optical Photometry of V709 Cas Using TESS : Refined Periods and Accretion Geometry

Abstract

Utilizing high-cadence and long-term optical photometry from the Transiting Exoplanet Survey Satellite (TESS ), we conducted a time-resolved timing analysis of the Intermediate Polar, V709 Cas. Our analysis reveals key characteristics of this system: an orbital period of 5.3329 $\pm$ 0.0002 h, a spin period of 312.7478 $\pm$ 0.0002 s, and a beat period of 317.9267 $\pm$ 0.0002 s. These periods represent a significant refinement over the results of previous studies. These analyses demonstrate that V709 Cas is primarily a disc-overflow accretor, with accretion predominantly occurring via a disc. However, the analysis also reveals epochs where stream-fed accretion is a dominant accretion process. Time-resolved analysis of 20 s short cadence data obtained from sectors 57 and 58 reveals the presence of distinct first harmonics of the spin and beat frequencies. This finding indicates the presence of double peak spin modulation, a characteristic signature of two-pole accretion onto the white dwarf.