Simulated near-infrared CMDs of field (l = 0°, b = 1°) with the CMD selection box in red. This simulation was done using the Fux (1999) disc-particle distance distribution, a mean extinction A₅₅₀ = 7.7 with a dispersion of 0.8 mag, the isochrones of Bressan et al. (2012), a constant SFR, the Chabrier (2001) lognormal IMF, and Gaussian metallicity distribution centred at −0.21 with a dispersion of 0.5 dex. The number of stars is arbitrary. The field’s black circles correspond to a hundred simulated stars selected using the same Q and I_max critera applied and detailed in Sect. 2.1.