Left panel: Kiel diagram (log g vs. T_eff) for our sample stars. Overplotted are the rotating Geneva (Ekström et al. 2012; black) and Bonn (Brott et al. 2011; red) tracks for the mass range 20–60 M_⊙, with initial rotation velocities of 40% of their critical speed. Right panel: corresponding spectroscopy HR diagram (sHRD, see text), with both ordinate-axes proportional to L∕M. The Eddington Γ_e has been calculated with solar Helium content, assumed to be completely ionized. Symbols in both panels as in Fig. 1.