Mapping M Dwarf Metallicities
We use distances derived from Gaia parallaxes cross-matched with SDSS, WISE and 2MASS photometry to assemble a sample of approximately 2 million M dwarfs, defined as stars with SDSS colors redder than r-i = 0.3 and i-z = 0.2. Previous work has found relations between SDSS r-z and WISE W1-W2 colors and the effective temperature and metallicities of cool stars (3550-4200 K). Using our sample and these previously derived relationships, we measure these stars' metallicities and effective temperatures. We calculate the metallicity distribution gradient as a function of galactic height for M dwarfs within 1000 pc of the Sun, which ultimately lends insight to the kinematic and chemical evolution of the Galaxy.