Spectroscopic HRD of the sample stars with data-points colour-coded and size-scaled according to their v_mic value, as indicated in the legend. Overplotted, we have the Brott et al. (2011) evolutionary tracks for single stars with solar metallicity and initial rotational velocity V_rot = 300 km s⁻¹; the Eddington limit (horizontal dotted line); the observed HD limit (gray solid thick lines) and the temperature boundaries corresponding to each spectral type (red almost vertical lines). Error bars are omitted for clarity. For more information see Sect. 5.