Evolution of angular rotation velocity profiles for three different values of j_a. The dashed black profile corresponds to just before mass transfer (“1”) and subsequent profiles, plotted in alternating line types of progressively lighter colours, correspond to end of mass transfer (“2”), return to thermal equilibrium (“3”), main sequence (between “3” and “4”), before first dredge-up (“5”) and after first dredge-up (“6”). The last two profiles demonstrate the spin-up of the core after the main sequence. Note the different y scales.