Z Draconis with two companions in a 2:1 mean-motion resonance

Jinzhao Yuan, Hakan Volkan Senavci, Shengbang Qian +1

All available mid-eclipse times of the eclipsing binary Z Draconis are analysed, and three sets of cyclic variations with periods of 20.1, 29.96 and 59.88 yr are found. The low-amp…