The radial velocities of Cepheid Polaris are measured using 237 Reticon spectra. The data show a pulsation period of 3.9746 + or - 0.0008 days and RV amplitude 2K = 1.50 + or - 0.08 km/s. It is shown that Polaris has been undergoing a steady period increase, consistent with redward evolution across the instability strip. A post-1980 drop in amplitude and the redward evolution of Polaris suggest that the source is leaving the strip and may cease its pulsation as early as 1995.
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Dinshaw et al. (1989) studied this question.