SEARCH Articles Figures Tables Evolution of the interior of a thermally pulsing AGB star. Locations of the lower boundary of the convective envelope, the H-burning shell, and lower edge to the He-shell are labelled. Two convective thermal pulses are shown. Key to understanding the s-process are the shaded bars of which the middle one is overwritten with a P and 13C - see text. From Busso, Gallino Wasserburg . [Publishers Imprint]