Abundance analysis of benchmark M dwarfs

Context . Abundances of M dwarfs, the most numerous stellar type in the Galaxy, can enhance our understanding of planet formation processes. They can also be used to study the chemical evolution of the Galaxy, where α-capture elements play a particularly important role. Aims . We aim to obtain the abundances of Fe, Ti, and Ca for a small sample of well-known M dwarfs for which interferometric measurements are available. These stars and their abundances are intended to serve as a benchmark for future large-scale spectroscopic studies. Methods . We analysed spectra obtained with the GIANO-B spectrograph. Turbospectrum and the wrapper TSFitPy were used with MARCS atmospheric models to fit synthetic spectra to the observed spectra. We performed a differential abundance analysis in which we also analysed a solar spectrum using the same method and then subtracted the derived abundances line by line. The median was taken as the final abundance of each element and each star. Results . Our abundances of Fe, Ti, and Ca mostly agree within the uncertainties with other values from the literature. However, there are few studies to compare with.