Polaris the Cepheid: still pulsating

Krockenberger, M., Noyes, R.W., & Sasselov, D.D. 1994, BAAS, 26, 1366.

ABSTRACT

We present high resolution spectra of Polaris (alphaUMi, taken with the AFOE
in May and September of 1994. The quality of the data allows velocity
measurements accurate to ~50 m/sec.  We find that Polaris is pulsating with an
amplitude of ~0.9 km/sec. This could mean that the pulsation amplitude of
Polaris is increasing after having gone through a minimum or that the
amplitude has stabilized at the measured value after having declined for this
century.

We also compare the time of the velocity maximum with previous measurements to
find that a significant change in phase has occurred.  This could be due to a
change in period or a phase jump of ~180 deg.