a, b) Show the (V − I)₀ versus M_I colour–magnitude diagram using values from microlensing techniques (open circles) and spectroscopy (filled circles). a) Shows the stars with  [Fe/H]  < 0 and b) the stars with  [Fe/H]  > 0. Each CMD also show the Y² isochrones (1, 5, 10, and 15 Gyr) from Demarque et al. (2004). For the metal-poor sample the isochrones have  [Fe/H]  = −0.6 and for the metal-rich sample  [Fe/H]  =  + 0.3. The spectroscopic and microlensing values have been connected with a dashed line for each star (4 stars do not have microlensing values).