On the Optical Spectrum of Mu Cephei

High resolution spectra of M-type supergiant μ Cep are analyzed. The movements in the atmosphere of this star are highly supersonic and variable with depth. The lines forming in deeper layers show the widths corresponding to 30 km/s. The lines forming in outer layers are much wider, 50 km/s. At the same time, the microturbulent velocity is low, from 4.0 to 4.5 km/s. The atmosphere of μ Cep is slightly metal deficient with [Fe/H] = --0.4.