Fitting stellar parameters, and compilation of the stellar irradiation for two examples, TW Hya (left) and AB Aur (right). The upper plots show measured photometric fluxes (coloured symbols) as function of wavelength λ, in comparison to our best fitting, reddened Phoenix stellar atmosphere model spectrum (black), and the averaged observed FUV data (orange). The lower plots show the de-reddened surface intensities I_ν(r = R_⋆) (black), and the averaged, de-reddened FUV data (λ> 91.2 nm, red). The blue lines show fits to de-absorbed X-ray data, using a two-component X-ray gas emission model (energy E> 0.1 keV). The dashed grey line marks the EUV regime in between, which is assumed to be absorbed by neutral hydrogen between the star and the disk and hence disregarded in the disk model. The dashed magenta lines show quick parametric fits to the UV and X-ray data, see Eqs. (A.1) and (A.2) and text, not used for the TW Hya and AB Aur models.