Exemplary comparison of the best fitting model spectrum (red line) with normalized observation (black line; X-shooter spectrum taken on March 23, 2019, i.e., 2 458 565.8693 HJD). Light colors mark regions that have been excluded from fitting, e.g., due to the presence of interstellar or telluric lines. Residuals, χ, are shown as well. The optical spectrum only exhibits lines of H, He, Mg, Ca, and Fe.