Speaker
Description
M dwarfs are the most abundant stars in the Galaxy and key targets for stellar population and exoplanet studies, yet their molecularly rich spectra make chemical analysis difficult. This work presents a set of complementary methods to improve metallicity and abundance determinations in M dwarfs using photometry, low- and high-resolution spectroscopy, and data-driven techniques.
Wide FGK+M binary systems serve as empirical calibrators, allowing the well-characterised FGK primaries to anchor the chemical analysis of their M-dwarf companions. We first develop empirical metallicity relations based on Gaia, 2MASS, and CatWISE photometry, using Bayesian regression and neural networks. We then refine the reference abundances of the FGK primaries through high-resolution analysis, including new C and O measurements and updated odd-Z iron-peak abundances. Building on these benchmarks, we introduce a low-resolution spectroscopic method that derives [X/H] for 15 elements in over 770 M dwarfs from CAFOS spectral indices, recovering trends consistent with high-resolution studies. Finally, we analyse new CARMENES high-resolution spectra of M-dwarf secondaries, confirming their metallicity agreement with FGK companions. These approaches provide scalable, reliable tools for characterising M dwarfs in forthcoming large surveys and missions.