THE RADIAL-VELOCITY VARIABILITY OF ALPHA-PERSEI - A LOW-AMPLITUDE CEPHEID OUTSIDE THE INSTABILITY STRIP

Precise radial velocity measurements (sigma similar to 35 m s(-1)) are presented for the F5 supergiant alpha Per. Low-amplitude variations w ith a 2K amplitude of 300 m s(-1) and a period of 87.7 days, or a poss ible (but less likely) period of 9.80 days, are detected. The favored period of 87.7 days most likely arises from rotational modulation by s urface features or nonradial pulsations. If the radial velocity variat ions of alpha Per result from pulsations, then this star may represent a case for Cepheid-like pulsations in a star just outside of the know n boundary of the Cepheid instability strip.