HR diagram for the six SB2 systems investigated in this paper. The colors differ according to the object. The evolutionary tracks (solid lines) of the labeled masses as well as the ZAMS (dash-dotted line), and the isochrones (dotted lines plotted with the same color as the reference system) for solar composition are displayed. The dash-dotted blue lines show the δ Sct instability strip of Breger & Pamyatnykh (1998). The orange dash-dotted lines show the theoretical edges of the γ Dor instability strip of Warner et al. (2003). The two stars plotted as filled squares have a standard solar composition.