2008MNRAS.387L...1U

We present an analysis of high-resolution spectroscopic observations of Polaris B, the optical companion of the Polaris Ab system. The star has a radial velocity of -16.6 to -18.9km/s, and a projected rotational velocity v sini =110 km/s. The derived atmospheric parameters are: T_eff= 6900 K; logg =4.3; V_t= 2.5km/s. Polaris B has elemental abundances generally similar to those of the Cepheid Polaris A, although carbon, sodium and magnesium are close to the solar values. At a spectral type of F3 V Polaris B has a luminosity of 3.868L_☉, an absolute magnitude of +3.30 mag, and a distance of 109.5 pc. The mass of the star is estimated to be 1.39 M_☉, close to a mass of 1.38±0.61M_☉ for the recently resolved orbital period companion Polaris Ab observed by Evans et al.