Chromospherically active stars. XXIII. The triple system HD 7205 = QU Andromedae

HD 7205 is a recently discovered visual binary. The primary star is a chromospherically active, single-lined binary, making the system triple. From spectroscopic observations, the orbit of the primary has a period of 18.01335 days and a moderate eccentricity of 0.197. The primary's spectral type is G8 IV-V. The unseen secondary of the short-period binary is likely an M dwarf, while the visual binary secondary is probably a K3 dwarf. From solar-abundance evolutionary tracks, the primary has a mass of similar to1.0 M-circle dot and an age of about 10 Gyr. It has evolved off the main sequence and is approaching the base of the red giant branch. Its rotation period of 21.3 days is significantly different from its pseudosynchronous rotation period of 14.6 days, making it an asynchronous rotator.