Spectral fitting. The observed spectrum is plotted by the black line, the blue one is the best fit using PYTERPOL code (see Table 4), for which the contribution of the hot source was included into the calculations. For the comparison, we also show the best fit by a single star (T_eff = 12 580 K, log g =4.2, and v_rot =11 km s⁻¹, solar composition) without the contribution of a hot source, the dotted violet line.