H${}_{\alpha }$ line as an indicator of envelope presence around the Cepheid Polaris Aa ($\alpha UMi$)

I. A. Usenko, A. S. Miroshnichenko, V. G. Klochkova +1

We present the results of the radial velocity ($RV$) measurements of metallic lines as well as H${}_{\alpha }$ (H${}_{\beta }$) obtained in 55 high-resolution spectra of the Cepheid $\alpha$ UMi (Polaris…