Detailed profiles of permitted Fe ii lines (middle and right-hand panels) strongly depend on φ. The prominent emission lines form in a circumbinary disc and stay static (within ±3 km   s^-1) around the γ-velocity. The B/R emission peak ratios (see bottom panel of Fig. 14) periodically vary due to Doppler shifting lines formed in the orbiting primary star. It causes the triple-peaked emission lines around φ = 0.4–0.5. We observe in Si ii λ6347 static line emission from the disc modulated by Doppler shifting absorption in the primary (left-hand panels).