Evolution of the centre of the dip s_c obtained using a full model (full line) and evolution of the spin parameter of the inertial mode obtained using a core-only model (dotted line). The dash-and-dot blue line shows the spin parameter of the inertial mode in the case of a uniform density core (analytical model). The light blue curves refer to the model 1z, orange curves to the model 2m, and red curves to the model 3t.