CPD −57° 3509 in the log T_eff-log g diagram (black dot, this work). Previous analysis results of the star obtained by use of grids assuming solar helium abundance are indicated by St. Andrew’s crosses, from the work by Hunter et al. (2009, high-gravity solution) and McSwain et al. (2009, low-gravity solution). Analysis results for other He-strong stars from the literature are also shown from Zboril et al. (1997, circles), Leone et al. (1997, diamonds), Hunger & Groote (1999, squares), and Cidale et al. (2007, triangles), marked in grey. Two stars common to all four analyses are highlighted, HD 58260 (red symbols) and HD 64740 (blue symbols). Where available, 1σ error bars are displayed. Overlaid are Geneva evolution tracks for rotating stars, computed 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) = 7.0, 7.1, 7.2, and 7.3 are also displayed (dotted lines), as well as the position of the zero-age main sequence (ZAMS, long-dashed line).