TLUSTY/XTGRID spectral energy distribution. The green data points are taken from the VizieR photometric data service and used in the spectral decomposition to constrain the dilution factor. Over the GALEX FUV and NUV ranges, we show theobserved IUE spectra (black). The composite model (grey) is the sum of the  TLUSTY sdOB (blue) and the ATLAS G1V(red) models. The shaded regions mark various filter pass-bands.