Application of isochrones in the Kiel diagram (left panel), and two CMDs from Gaia DR3 and VVV DR4 data (right panel). The left panel shows the determined T_eff and log g parameters from Sect. 3.2 for our sample stars, overlaid with 10 Gyr Y² isochrones for four different metallicities. The CMDs in the right panel are identical to those in Fig. 2, but we plot isochrones of −0.7 dex in [Fe/H]. We applied a distance of 2.0 kpc and E(B − V) of 1.1 mag for the solid line and a distance of 4.47 kpc and E(B − V) of 1.0 mag for the dashed line. Although both lines closely follow the RGB sequence, the locations of our sample stars on the RGB differ. They appear as faint and bright RGB for the 2.0 kpc and 4.47 kpc lines, respectively. The location of the sample stars on the isochrone at 2.0 kpc is more comparable to their positions in the Kiel diagram.