Mid-eclipse times of KIC 10544976

This effect is usually interpreted either as the gravitational interaction among circumbinary bodies and the host binary - known as the light travel time (LTT) effect - or as the quadrupole moment variations in one magnetic active component - known as the Applegate mechanism. In this study, we present an analysis of the ETV and the magnetic cycle of the close binary KIC 10544976.

This system is composed of a white dwarf and a red dwarf in a short orbital period (0.35 days) and was monitored by ground-based telescopes between 2005 and 2017 and by the Kepler satellite between 2009 and 2013. Using the Kepler data, we derived the magnetic cycle of the red dwarf by two ways: the rate and energy of flares and the variability due to spots. Both methods resulted in a cycle of ~600 days, which is in agreement with magnetic cycles measured for single low-mass stars.