The Pulsation Mode of the Cepheid Polaris
Abstract
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 <Mv>=-3.07+-0.01 s.e., average effective temperature of <Teff>=6025+-1 K s.e., and intrinsic color of (<B>-<V>)o=0.56+-0.01 s.e., which match values obtained previously from the photometric parallax for a space reddening of E(B-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.
Keywords
Cite
@article{arxiv.1211.6103,
title = {The Pulsation Mode of the Cepheid Polaris},
author = {David G. Turner and V. V. Kovtyukh and Igor Usenko and N. Gorlova},
journal= {arXiv preprint arXiv:1211.6103},
year = {2015}
}
Comments
To appear in ApJL