[Mg/Fe] vs. age diagrams. Upper left panel: predictions of models of the thin disk at different radii: 4 kpc in gray, 6 kpc in purple, 8 kpc in blue, 10 kpc in green, 12 kpc in orange, 14 kpc in red (see Chiappini 2009; Grisoni et al. 2017, 2018). In the other panels the observational data are shown for our sample in different bins of guiding radius. The black lines in the various plots mark the “forbidden region” as defined in Chiappini et al. (2015). The red dots are the young α-rich stars selected in our sample. We report the 1σ_age error bars.