Abundance ratios [X/Fe] as a function of stellar age. Large (red) filled circles refer to Kepler LEGACY stars and small (blue) filled circles to solar twins from Nissen (2016). The lines show maximum likelihood linear fits to the data with errors in both coordinates taken into account. The Sun, shown with the ⊙ symbol, was not included in the fits. Zero points and slope coefficients for the fits are given in Table 3.