Influence of [α/Fe]on StarHorse ages. We plot the age residuals —i.e. the difference between ages used in the present study and the StarHorse ages with a modified alpha abundance— as a function of the adopted ages. Each panel corresponds to the amount of change to the [α/Fe]before recalculating the ages(red, ±0.1 and ±0.2 dex). Mean scatter (σ) and bias (Δ) are also calculated using a bootstrap sampling.