Upper panel, top: density-weighted mean (Eq. (11)) of the mass absorption coefficient, , for the interval between 1.2 and 110 R_∗, as a function of wavelengths and for dwarf models with = 3 × 10⁶ K and f_X = 0.03. Solar abundances following Asplund et al. (2009) were adopted. Dashed: approximate, radius-independent (Eq. (9)), using only solar abundances and K-shell opacities with cross sections from C iv (with threshold at 35.7 Å), N iv (27.0 Å), O iv (20.8 Å), Ne iv (13.2 Å), Mg iv (9.0 Å), and Si iv (6.4 Å). The C v edge (at 31.6 Å) appears to be unresolved in our frequency grid. Dotted: same as dashed, but with nuclear processed CNO abundances as derived for ζ Pup by Bouret et al. (2012). The nitrogen abundance is more than a factor of 10 larger than the solar abundance. Dashed and dotted lines also serve as a guideline for comparison with similar figures. Bottom: relative standard deviation, (see Eq. (12)), for the same models. The dotted line denotes a relative scatter of 15%. Lower panel: as above, but for supergiant models.