Time evolution of Ω. The Ω profile is taken from the interpulse of the “250 5” model that is shown in Fig. 3. Grey regions are the convective envelope during TDU (left) and the TP (right), dashed black contour lines show constant log₁₀(r/R_⊙), coloured contour lines show Ω values in linear range (the darker the contour line, the lower Ω). Model numbers 59 400, 60 000, and 60 500 correspond to the three time steps in Fig. 3, and the vertical axis of this figure corresponds to the horizontal axes of the “250 5” panels in Fig. 3. The contraction of the region leads to a steeper Ω gradient in the ¹³C-pocket region.