Long-period radial-velocity variations of Arcturus

Precise measurements of the radial velocity of Arcturus were obtained on 43 occasions between 1981 and 1985. The measurements show a 500 m/s range, confirming the radial velocity variability of Arcturus. Multiperiod models which give a good representation of the velocities are derived using a least-squares technique. The models also fit the velocities of Smith et al. (1987). It is suggested that the small-amplitude short-period components of the models could be analogous to the solar five-minute oscillations. The best-fitting models require the largest-amplitude component to have a period of at least 640 days.