A Step towards Unveiling the Nature of Three Cataclysmic Variables: LS Cam, V902 Mon, and SWIFT J0746.3-1608

TL;DR

This study uses TESS data to analyze three cataclysmic variables, revealing superorbital and beat periods, accretion mode changes, and potential classifications, advancing understanding of their accretion dynamics.

Contribution

It provides new timing analyses of LS Cam, V902 Mon, and SWIFT J0746.3-1608, identifying previously undetected periods and suggesting their accretion modes and classifications.

Findings

LS Cam exhibits a superorbital period of ~4.025 days and superhump periods of ~3.30 h and 3.70 h.

V902 Mon and SWIFT J0746.3-1608 show beat periods of ~2387 s and ~2409 s, respectively.

V902 Mon has an orbital period derivative of (6.09 ± 0.60) × 10^{-10}.

Abstract

We have carried out detailed time-resolved timing analyses of three cataclysmic variables (CVs) namely LS Cam, V902 Mon, and SWIFT J0746.3-1608, using the long-baseline, high-cadence optical photometric data from the Transiting Exoplanet Survey Satellite (TESS). Our analysis of LS Cam observations hints the presence of a superorbital period of $\sim$ 4.025$\pm$0.007 d along with negative and positive superhump periods of $\sim$ 3.30 h and 3.70 h, respectively. These results can be explained as an interaction of nodal and apsidal precession of the accretion disc with orbital motion. For the other two sources, V902 Mon and SWIFT J0746.3-1608, we have found evidence of a beat period of 2387.0$\pm$0.6 s and 2409.5$\pm$0.7 s, respectively, which were not found in earlier studies. Our results presented in this study indicate the change in the accretion mode during the entire observing period for both sources. For V902 Mon, an apparent orbital period derivative of (6.09 $\pm$ 0.60) $\times 10^{-10}$ was also found. Moreover, the second harmonic of orbital frequency dominates the power spectrum of SWIFT J0746.3-1608, suggestive of ellipsoidal modulation of the secondary star. Present analyses suggest that LS Cam could be a superhumping CV whereas V902 Mon and SWIFT J0746.3-1608 are likely to be variable disc-overflow accreting intermediate polars.