High Resolution Optical Spectra of the Dormant LBV Star P Cyg

High resolution optical spectra ( R = 60 000) of the dormant LBV star P Cyg were obtained on the BTA telescope in the wavelength range Δλ = 477- 780 nm. After performing a detailed identification of different types lines (photospheric absorptions, permitted and forbidden emissions, components of lines with profiles of P Cyg type), we studied the variability of their profiles and patterns of radial velocities. The average radial velocity from positions of forbidden emissions ([N II] 5754.64, [Fe II] 5261.62, [Fe II] 7155.14 and [Ni II] 7377.83 Å) is accepted as the system V_sys = - 34 ± 1.4 km/s. About a dozen photospheric absorptions of CNO-triad ions and Si III are found, their stable position, V_r(abs) = - 73.8 km/s, shifted relative to V_sys at about - 40 km/s, indicates that these absorbtions are formed in the pseudophotosphere region. The high-excitation emissions ([O I] 5577, 6300, 6363 Å, [O III] 4959 and 5007 Å, as well as He II 4686 Å) are absent in the spectra. The radial velocity V_r(DIBs) = - 11.8 km/s according to the position of numerous DIBs is consistent with the position of the interstellar components of the D-lines Na I and K I forming in the galactic Perseus arm. An excess of color E(B- V) = 0.34 ±0.03^m and interstellar absorption A_v = 1.09^m were determined by measurements of equivalent widths of nine DIBs.