Milky Way Mapper decoded abundances – I. Shared disc enrichment patterns

ABSTRACT Elemental abundances in the Milky Way disc trace its star formation and enrichment history, but predicting these abundances from theory is limited by uncertain nucleosynthetic yields and poorly constrained chemical evolution models. Large surveys provide many abundances that enable multidimensional insight. However, having so much data available complicates joint visualization and physical interpretation. Here, we examine the element abundances of 70 057 red giant stars from the Milky Way Mapper survey ([Fe/H] $\gt -1$), using 16 elements (O, Mg, Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Ce, and Nd). To tackle the challenges of joint-interpretation of these elements, we build a generative data-driven model, expressing each star’s abundance vector as a linear combination of a few (4) latent nucleosynthetic patterns. These patterns are shared among the population but vary in fraction between stars. The model accurately generates the measured abundances, with $\chi ^2 \lt 3$ (5) for $\sim$ 80 per cent (95 per cent) of stars. Model failures, where stars’ abundances are not generated by the latent basis, reveal accreted material and the role of multiple channels of metal-poor disc enrichment. We associate the recovered patterns, which represent high-precision ($\sigma _P \sim 3$ per cent) nucleosynthetic channels, with specific enrichment sources: (early and late) core-collapse supernovae, supernovae Type Ia, and asymptotic giant branch stars. We subsequently explore how the dominance of enrichment channels varies across age, metallicity, and spatial extent of the disc, and show that enrichment patterns tightly couple to orbital properties. Mean pattern fractions vary smoothly with enrichment, and change rapidly across the valley between the high- and low-$\alpha$ sequences. Our results provide a framework for improving our understanding of Galactic evolution in the Milky Way.