A multi-wavelength study to probe AGB nucleosynthesis and stellar evolution.

The main aim of the proposed research is to improve our understanding of the late stages of stellar evolution and of the nucleosynthesis in Asymptotic Giant Branch (AGB) stars. The study of the complex and chemically peculiar AGB stars helps us to shed light on two currently much debated topics in astrophysics, namely, the various mixing processes that occur in stellar interiors and the galactic chemical enrichment of the elements heavier than iron. Despite their importance, several crucial mixing processes (e.g., third dredge-up) of AGB stars are still not understood due to the lack of accurate observational constraints. Today, the availability of novel instrumentation for high-resolution data, together with the accurate distance estimates from Gaia, present an excellent opportunity to determine such observational constraints. We aim at providing these constraints by performing a detailed abundance study of a new and diverse sample of AGB stars. In particular, we will conduct both optical and infrared spectroscopic analysis, as these wavelengths provide essential and complementary information on AGB nucleosynthesis. In addition, we will compare the collected high-precision observational abundances with predictions from several AGB nucleosynthesis models. Lastly, we will expand our study from reference stars to large spectroscopic surveys by developing an automated tool to determine the s-process abundances of evolved stars in these surveys.