Simulations of the Hγ, He I 4388, 4471, and Mg II 4481 spectral lines in the disentangled spectra of a mock system composed of an O6.5 III primary. Red and blue spectra are the synthetic models. We entangle 12 observed spectra with synthetic models of a MS secondary (left panels), and with synthetic models of a stripped helium star (right panels; Götberg et al. 2018). The secondary spectra were convolved by a rotational profile of 100 km s⁻¹. Black and green spectra are the disentangled spectra. Companions with flux ratios lower than 0.02 would not have been detected from our data. The spectra are shifted vertically for clarity. We correct for the dilution by taking adopted values of 95% for the primary and 5% for the secondary for all the simulations. (a) B5 V MS secondary with T_eff = 15.0 kK, log g = 4.0 [cgs] and f2 = f1 = 0.04. (b) Stripped He secondary with T_eff = 95.0 kK, log g = 5.33 [cgs] and f2 = f1 = 0.02. (c) B7 V MS secondary with T_eff = 12.0 kK, log g = 4.0 [cgs] and f2 = f1 = 0.02. (d) Stripped He secondary with T_eff = 69.1 kK, log g = 5.27 [cgs] and f2 = f1 = 0.008. (e) A1 V MS secondary with T_eff = 8.0 kK, log g = 4.0 [cgs] and f2 = f1 = 0.006.