UVES spectrum of CVSO 104 A (black dots) observed on JD = 2 459 180 in three spectral regions around 6200 Å (top), 6400 Å (middle), and 6700 Å (bottom). In each box, the synthetic spectrum, which is the weighted sum of two standard star spectra mimicking the primary and secondary component, is overplotted with a full red line. Prominent lines from the primary and secondary component are marked with a and b, respectively. The hatched green regions denote the level of the veiling. The residual spectra obtained by the subtraction of the photospheric template are displayed in the lower panel of each box with a blue line.