Physical Parameters of Superhumps in Five Dwarf Nova Systems Based on TESS Observations

Abstract

This study presents a detailed analysis of five cataclysmic variable systems of the dwarf nova class: Gaia21djh, Gaia19bwr, Gaia21akq, Gaia21enu, and Gaia18cjn. Using photometric data from the TESS space telescope and the ASAS-SN sky survey archive, the superhump periods (P_sh) and orbital periods (P_orb) for three SU UMa-type systems were determined. For Gaia21djh, P_sh = 0.08214 days and P_orb = 0.0786 days were obtained; similar values were determined for Gaia19bwr and Gaia21akq. For Gaia18cjn and Gaia21enu, the presence of stable superhumps was not confirmed, although Gaia18cjn shows an orbital period of P_orb = 0.189 days. The analysis of physical parameters, including mass ratios q, component masses M₁ and M₂ and radii R₁ and R₂ showed that all SU UMa systems have low q values (<0.3) consistent with tidal instability. For example, Gaia21akq has q = 0.24 ± 0.03, which supports previous theoretical models. The study of superoutburst parameters revealed significant variability in the duration of different phases. Gaia19bwr exhibited the longest plateau phase duration (D_P = 9.6 ± 1.7 days), while it was D_P = 6.5 ± 0.6 days for Gaia21akq. The largest superoutburst amplitudes were observed in Gaia21djh (A_SO = 4.3 ± 0.2) and Gaia19bwr (4.2 ± 0.3). The obtained results are consistent with the thermal-tidal instability model for SU UMa-type systems and highlight the importance of high-precision photometric observations in studying accretion disk dynamics.