Simulations of HeIλ5875 line profile variation based on the TLUSTY (Hubeny & Lanz 1995) stellar atmosphere models. We assume that we have two stars with T_eff = 32.5 [kK] and logg = 4.0, for the primary we set up two regimes of v sin i, namely 200 and 300 km s⁻¹, without orbital velocity K1 = 0 km s⁻¹ (left and right panel, respectively). In the case of the secondary component, we assume it has ten random K2 values in the range from 0 to 50 km s⁻¹ and constant v sin i of 100 km s⁻¹. Then we modelled the composite spectrum with the different contributions of the secondary component by varying the flux ratio F2/F_total from 0.1 to 0.3.