Different Eddington factors inside a 285 M_⊙, non-rotating, main-sequence model with log L/L_⊙ = 6.8 and T_eff = 46 600 K (cf. Fig. 9 and Appendix A). The shaded areas mark the different convection zones and the hatched area marks the region with a density inversion. The radius of the non-inflated core is denoted as r_core (defined in Sect. 4). The black dashed horizontal line is drawn at Γ = 1 for convenience.