Left panel: Model DMIN. Top row : Evolution of He density at two evolved times marked in the graph. The density scaling is the same as in Fig. 1. Bottom row : Evolution of Fe density at the same two times with different scaling. Right panel: Model LMIN. Top row : Example of map of the temporal evolution of helium density at two evolved times marked in the graph. The density scaling is the same as for the total density of this model in the top row of Fig. 2. Bottom row: Map of the temporal evolution of iron density at the same two times, with significantly different density scaling.