THE PULSATION MODE OF THE CEPHEID POLARIS

A previously derived photometric parallax of 10.10+/-0.20 mas, d = 99+/-2 pc, is confirmed for Polaris by a spectroscopic parallax derived using line ratios in high dispersion spectra for the Cepheid. The resulting estimates for the mean luminosity of < M-V > = -3.07+/-0.01 s.e., average effective temperature of < T-eff > = 6025+/-1 K s.e., and intrinsic color of (< B > - < V >)(0) = +0.56+/-0.01 s.e., which match values obtained previously from the photometric parallax for a space reddening of EB-V = 0.02+/-0.01, are consistent with fundamental mode pulsation for Polaris and a first crossing of the instability strip, as also argued by its rapid rate of period increase. The systematically smaller Hipparcos parallax for Polaris appears discrepant by comparison.