Position of the stars (filled squares) in the log g − log T_eff diagram. Evolutionary tracks are from Schaerer et al. (1993). The numbers correspond to stellar masses in units of solar mass. Red lines represent evolutionary tracks for a star with Z = 0.04. The stars CD-25 6606, HD 49841, HD 84734, and HD 85205 are subgiant stars about to begin their ascent of the red giant branch, like S 190, a D′-type symbiotic star (open square) that is also barium enriched (Smith et al. 2001).