Testing the third body hypothesis in the Cataclysmic Variables LU Camelopardalis, QZSerpentis, V1007 Herculis and BK Lyncis

TL;DR

This study investigates whether a third body could explain long photometric periods in four cataclysmic variables by modeling orbital dynamics and perturbations, providing evidence for third bodies in three of them.

Contribution

It introduces a comprehensive analytical approach to test the third body hypothesis in CVs, including orbital stability and secular perturbations, with new estimates of third body masses.

Findings

Supports the third body hypothesis in LU Cam, QZ Ser, BK Lyn

Marginal evidence for a third body in V1007 Her

Third body masses range from 0.63 to 97 Jupiter masses

Abstract

Some Cataclysmic Variables (CVs) exhibits a very long photometric period (VLPP). We calculate the properties of a hypothetical third body, initially assumed on circular--planar orbit, by matching the modelled VLPP to the observed one of four CVs studied here: {\sl LU Camelopardalis} (LU Cam), QZ Serpentis (QZ Ser), V1007 Herculis (V1007 Her) and BK Lyncis (BK Lyn). The eccentric and low inclination orbits for a third body are considered using analytical results. The chosen parameters of the binary components are based on the orbital period of each CV. The smallest corresponding semi-major axis permitted before the third body's orbit becomes unstable is also calculated. A first-order analytical post-Newtonian correction is applied, and the rate of precession of the pericentre is found, but it can not explain any of the observed VLPP. For the first time, we also estimate the effect of secular perturbations by this hypothetical third body on the mass transfer rate of such CVs. We made sure that the observed and calculated amplitude of variability was comparable too. The mass of the third body satisfying all constrains range from 0.63 to 97 Jupiter masses. Our results show further evidence supporting the hypothesis of a third body in three of these CVs, but only marginally in V1007 Her.