GALAH: A Survey of Solar Elements
Abundance ratios in GALAH DR2 and their implications for nucleosynthesis
We construct median sequences of [x/mg] vs. [[mg/h] for 21 elements, separating the and stellar populations through cuts in [mg/fe.Using a sample of 70 924 stars from the second data release of the second data release of the galex adaptive large area large array for surveys (galah) optical spectroscopic survey, we construct median sequences of [x/mg] vs. [[mg/h] for 21 elements, separating the and stellar populations through cuts in [mg/fe.The separation between the two [x/mg] sequences indicates the relative importance of prompt and delayed enrichment mechanisms, while the slopes indicate metallicity dependence of the yields.We infer that about of solar c comes from corecollapse supernovae and from delayed mechanisms.We find core collapse fractions of for the fe-peak elements sc, ti, cu, and zn, with strong metallicity dependence of the core collapse cu yield.For the neutron capture elements y, ba, and la, we infer large delayed contributions with non-monotonic metallicity dependence.The separation of the [eu/mg] sequences implies that atleast of eu enrichment is delayed with respect to star formation.
