Evolution of the mass distribution in a uniformly rotating model with an initial mass of 0.675 M_⊙ when adding matter with j_a = 2 × 10¹⁷ cm²s^-1 at a rate of Ṁ = 10^-6M_⊙ yr^-1. The light-blue lines show the radius variation with mass in six models from just prior to mass addition to near critical rotation (ΔM ≃ 0.125 M_⊙). The black sections of the profiles indicate convective regions. The upper (dark-blue) envelope shows the evolution of the surface radius during mass addition.