Left: log g – T_eff (left) diagram for the sample stars together with comparison single stars from Martins et al. (2015). In the comparison sample, gray asterisks (brown stars) refer to stars less (more) massive than ~28 M_⊙. Filled symbols (stars and asterisks) refer to comparison stars with V sin i> 120 km s^-1. For clarity only a representative error bar for the comparison sample is shown. The evolutionary models including rotation of Ekström et al. (2012) are shown. Middle and right: log  (N/C) – log g diagram for stars with masses lower than 28 M_⊙ (middle) and higher than 28 M_⊙ (right). In all panels big symbols have the same meaning as in Fig. 4.