Structure of the envelope of a representative 0.6 M_⊙ model, for eight different envelope chemical compositions ranging from solar (upper left quadrant of upper panel) to a H-less mixture (lower right figure of lower panel). The boundaries of the outer convection zone(s) are indicated by heavy dots. The three dotted curves in each plot correspond to a Rosseland optical depth of 0.1, 1.0, and 10.0, from top to bottom. The boundaries of the instability strip for each case considered are indicated by blue and red vertical dotted lines.