Comparison of the model spectra (solid black line) and observed spectra (red symbols) of young solar-type stars (top κ¹ Ceti; middle π¹ UMa; and bottom EK Dra). The left side shows the bin-averaged spectra on a linear scale, while the right side shows them on a logarithmic scale. The bin size definition follows Fig. 3. The grey area represents the uncertainty of the model (factor of 3). The dashed black lines in the bottom panels indicate the spectrum after correction for the underestimation due to the insufficient resolution of the transition region (see the text for details).