Kiel diagram for HD 144941 (black dot). Geneva evolution tracks for rotating stars are shown for metallicity Z = 0.014 and an initial value of 40% of the critical rotation rate (Ekström et al. 2012, full lines). Corresponding isochrones for log τ (Myr) = 6.5 to 7.3, with0.2 spacing are also indicated (dotted lines, bottom to top), as well as the position of the zero-age main sequence (long dashed line). Positions of other He-strong stars analysed in analogy to the present work are shown (open black circles). Literature values for He-strong stars are marked by grey symbols: from Zboril et al. (1997, circles), Leone et al. (1997, diamonds), Hunger & Groote (1999, squares) and Cidale et al. (2007, triangles). Two stars common to all four literature analyses are highlighted, HD 58260 (red symbols) and HD 64740 (blue symbols). Where available, 1σ-error bars are displayed.