Chemical Properties of the Local Disk and Halo. II. Abundances of 3745 M
  dwarfs and Subdwarfs from Improved Model Fitting of Low-Resolution Spectra
  We present a model-fit pipeline to determine the stellar parameters of M-type
dwarfs, which is an improvement upon our previous work described in Hejazi et
al. 2020. We apply this pipeline to analyze the low-resolution (R~2000) spectra
of 3745 M dwarfs/subdwarfs, collected at the MDM Observatory, Lick Observatory,
Kitt Peak National Observatory, and Cerro Tololo Interamerican Observatory. We
examine the variation of the inferred parameter values in the HR diagram
constructed from their Gaia Early Data Release 3 (EDR3) parallaxes and optical
magnitudes. We also study the distribution of our stars in the abundance
diagram of [alpha/Fe] versus [M/H] and inspect the variation of their
metallicity class, effective temperature, and surface gravity as well as their
Galactic velocity components U, V, and W in this diagram. In addition, the
analyses of the stars' projected motions in the two-dimensional UV, VW, and UW
planes and the variation of their chemical parameters in these planes, and also
their distribution in the abundance-velocity diagrams are important parts of
this study. The precision of our model-fit pipeline is confirmed by the clear
stratification of effective temperature and chemical parameters in the HR
diagram, the similarity of the stars' distribution in the [alpha/Fe] versus
[M/H] diagram and in the metallicity-velocity planes with those from other
studies, revealing substructure in the abundance-velocity diagrams, and
chemical homogeneity between the components of a set of binary systems.
