The nucleosynthetic history of elements in the Galactic disk: [X/Fe] - age relations from high-precision spectroscopy
Lorenzo Spina

The chemical composition of stars is intimately linked to the Galaxy formation and evolution. In particular, knowledge of the [X/Fe]-age relations is a gold mine from which we can achieve a great understanding about the processes that governed the formation and evolution of the Milky Way. We used accurate age and chemical abundance determinations for a sample of 42 solar twins to outline the [X/Fe]-age relations of 24 species from carbon to europium. This data set revealed that each different class of elements shows a distinct evolution with time that relies on the various characteristics, rates and timescales of the nucleosynthesis' sites from which they are produced. Namely, the alpha-elements are characterized by a [X/Fe] decrement as time goes on. Strikingly, an opposite behaviour is observed for Ca. The iron-peak elements show an early [X/Fe] increase followed by a decrease towards the youngest stars. The [X/Fe] for the n-capture elements decrease with age. We also found that both [Mg/Y] and [Al/Y] are precise stellar clocks, with [Al/Y] showing the steepest dependence from age.