Internal properties (Kippenhahn diagram) of the 0.8 M_⊙ models with Y_ini = 0.248, 0.4, and 0.8 (top, middle, bottom) from the zero age main sequence to the end of central-helium burning. Green dashed lines delimit hydrogen burning regions (≥10 erg g^-1 s^-1); blue dashed lines delimit the helium burning regions (≥10³ erg g^-1 s^-1); dotted green and blue lines show the maximum energy production of H- and He-burning; hatched areas represent the convective zones. Timescales give the duration of each evolutionary phase.