Critical rotation velocities and frequencies, and their relation to stellar parameters for models between 1.5 and 4.1 M_⊙. The grey band shows the range of T_eff matching the observed spectra, the  +  sign shows the location of the best matching model in km s^-1 (see text). Top left panel: critical velocities on the main sequence for CLÉS models with α_ov = 0.2. The black line shows the line of models matching the observed v_eqsini with i = 90°. The grey lines show the models reaching their critical rotation frequency for different inclination angles for the observed v_eqsini (i = 40°,45°,60°,75° and 90°). The colours represent the values of different of the following quantities. Top right: R_eq for zero rotation (R_⊙). Bottom left: critical rotation frequency (d^-1). Bottom right: necessary differential rotation rate α for a model to reach f₁ at the pole with Ω_eq = Ω_crit.