Kippenhahn diagrams in radius and mass coordinates (left and right respectively) showing the evolution of the internal structure of the accreting models with [Fe/H] = −2 dex as in Fig. 1 for MLT, MLT++L.I., and MLT++ (from top to bottom). The x-axis is the time since the beginning of accretion on the 0.7 M_⊙ seed. The color maps show the temperature profiles. Areas highlighted with gray dots denote convective regions.