Hertzsprung–Russell diagram showing the nitrogen surface mass fraction of our evolutionary sequences with α_sc = 100 and α_sc = 0.33. The initial masses of the shown stellar tracks are evenly logarithmically spaced every 0.02 dex. Similarly to Fig. 2, a marker indicates a 50 000 yr time step, a circle indicates core hydrogen burning, and a diamond indicates core helium burning. Left: model sequences are nonrotating. Right: model sequences have an initial rotation velocity of 300 km s⁻¹.