Effect of the emission of an isotropic slow wind on the line profile (top) and its Fourier transform (FT, bottom), for two rotation speeds v sin i = 0 km/s (“null rotator” left) and v sin i = 100 km/s (“mid rotator” right). Top: The blue solid line shows (1) the rotating star, a rotationally broadened line profile convolved with Lorentzian, v_rot = 50 km/s, FWHM v_turb = 50 km/s. The red solid line shows (2) an isotropic slow wind halo with v_wind = 50 km/s and dispersion ≈ 20 km/s (total FWHM ≈ 65 km/s). The wind strength is 5% of the stellar equivalent width. The dash-dotted black line shows the combined profile of star and wind (sum of (1) and (2)). We note that the combined profile has a rounder (i.e. more boxy) shape than the pure stellar profile. Bottom: FT amplitude of the rotating star (blue), of the wind halo (red), and of the combined profile (star and wind, black).