Evolution of the absolute value of the rotation peak V_peak normalized by the initial value at time t=0, V_peak,t=0 as a function of mass loss ∆M/M. All simulations follow a similar track with a small variation, indicating that mass loss is the key parameter driving the decrease of rotation strength. The orange line is a fit of a simple function able to reproduce the shape of this evolutionary track. By measuring V_peak and mass loss at the present time, one can estimate the initial rotation peak (and the rotation peak at any given time). The gray shaded area indicates the phases where mass loss is dominated by stellar evolution or by tidal stripping (see also Fig. 9).