Long Photometric Cycles in Double Periodic Variables from Nodal Precession of a Tilted Accretion Disk

Abstract

We investigate whether the long photometric cycles observed in double-periodic variables (DPVs) can arise from nodal precession of a tilted accretion disk driven by the tidal torque of the companion. Within a simple analytical framework, we derive testable relations linking the long-to-orbital period ratio to the binary mass ratio, the normalized disk size, and the disk tilt angle $\beta$, which itself can be inferred from the long-cycle amplitude, orbital inclination $i$, and disk luminosity fraction. The model naturally reproduces the two observed long-cycle light-curve morphologies -- sinusoidal and double-hump -- distinguished by the geometric criterion $i+\beta \le 90^{\circ }$ versus $i+\beta >90^{\circ }$. Applying these relations to a sample of DPVs, we find that the inferred disk sizes are physically reasonable and consistent with independent light-curve modeling for a non-negligible subset of systems. Our results show that tidal nodal precession represents a viable and potentially important contributor to the long-period variability of DPVs and provide a quantitative framework for future observational and theoretical studies.

11 pages, 3 figures, 1 table. Accepted for publication in ApJ

References in corpus (10)

• The eclipsing LMC star OGLE05155332--6925581: a clue for Double Periodic Variables
• Accretion disk in the eclipsing binary AU Mon
• Fundamental parameters of the close interacting binary HD170582 and its luminous accretion disc
• New insights on the massive interacting binary UU Cassiopeiae
• Fundamental stellar and accretion disc parameters of the eclipsing binary DQ Velorum
• On the long cycle variability of the Algol OGLE-LMC-DPV-065 and its stellar, orbital and disk parameters
• Model for the long and orbital brightness variability of the $\beta$ Lyrae type binary OGLE-BLG-ECL-157529
• V4142 Sgr: a Double Periodic Variable with an accretor surrounded by the accretion-disk's atmosphere
• Stellar and accretion disk parameters of the close binary HD 50526
• Photometric study of hot Algol-type binaries with long cycles