Evolution of different parts of the bubble mass with stellar temperature T_eff for the simulations WR100V05 and WR100V05x5.5. The total X-ray-emitting bubble mass is M_X = M_WR + M_PN, where M_WR is the mass contributed by the stellar wind and M_PN that of the evaporated nebular matter. The symbols mark the models for which the data were evaluated. The evolution of M_X(PN1) of the hydrogen-rich PN1 reference simulation is shown for comparison (asterisks). The three bubble models of the WR100V05 simulation whose temperature profiles are displayed in Fig. 4 are marked along the top abscissa.