Measuring M-dwarf Metallicity through Spectroscopy of Common Proper Motion Binaries at Optical Wavelengths

M-dwarfs have a lifespan longer than the age of the Universe and therefore are useful in studying the formation of the Milky Way; understanding their metallicities provides a tracer of chemically older populations. We present a method for measuring M-dwarf metallicities by spectroscopy of F/G/K$+$M common proper motion binary pairs at optical wavelengths. We are in the process of determining an empirical relation between the molecular indices of the M-dwarf, such as CaH and TiO5, and the [Fe/H] metallicity of the Solar-like partner. We obtain high resolution spectroscopy of the F/G/K star for a detailed chemical abundance analysis, and low resolution spectroscopy of the M-dwarf to measure the molecular absorption features. Our analysis uses 50 binaries from the southern hemisphere over a broad range of metallicities and spectral types M0-M4. Future work includes applying this empirical relations to spectra obtained from the Sloan Digital Sky Survey (SDSS).