Parameter space covered by our APOGEE sample. Top panel: Kiel diagram (log g vs. T_eff) for the APOGEE DR17 catalogue (grey density). The black dots highlight the stars range for which our method provides chemical stellar age estimates. Bottom panel: Galactic distribution of the 178 825 APOGEE stars with spectroscopic ages in cylindrical coordinates (Z_Gal vs. R_Gal), based on the latest StarHorse distances (Queiroz et al. 2023). In both panels, the training sample (taken from the APOGEE-Kepler catalogue of Miglio et al. 2021) is overplotted in colours.