On the convective envelope of AGB stars

We discuss evolutionary computations investigating the efficiency of the co nvective "drift" which should affect the location of the inner boundary of the convective envelope in cool giant stars. We find that the drift is at t he work in structures undergoing the second dredge up, accelerating the sin king of the envelope into the inner He rich layers and producing smaller C- O cores at the onset of thermal pulses or at the C-ignition. However, such differences appear rather small, with mild consequences on the overall evol utionary scenario.