Precise radial velocities of giant stars XV. Mysterious nearly periodic radial velocity variations in the eccentric binary $\epsilon$ Cygni

Paul Heeren, Sabine Reffert, Trifon Trifonov +10

Using the Hamilton Echelle Spectrograph at Lick Observatory, we have obtained precise radial velocities (RVs) of a sample of 373 G- and K-giant stars over more than 12 years, leadi…