Temperature profile of the outermost layers of a 70 M_⊙ star computed with enhanced mass loss, as described in Sect. 4.2. Opacity peaks due to the ionization states of hydrogen, helium and iron and associated density inversions can be seen in panel (b) and panel (c) respectively. However, high mass-loss rates remove the outer layers containing the hydrogen and helium opacity peaks, moderating the specific entropy at the base of the convective envelope and the model is able to evolve until completion with reasonably large time steps.