# Value-added catalogs of M type stars in LAMOST DR5

## TL;DR

This paper presents new extensive catalogs of M giant and M dwarf stars from LAMOST DR5, including classifications, metallicity, and identification of carbon stars, enhancing stellar population data.

## Contribution

The work provides the first large-scale, detailed classification and catalog of M-type stars from LAMOST DR5, including subtypes, metallicities, and carbon star identification.

## Key findings

- Catalogs contain 39,796 M giants and 501,152 M dwarfs.
- Identified 289 carbon stars among M giants.
- Contamination rate of about 4.6% for M giants and 0.48% for M dwarfs.

## Abstract

In this work, we present new catalogs of M giant and M dwarf stars from the LAMOST DR5. In total, 39,796 M giants and 501,152 M dwarfs are identified from the classification pipeline. The template-fitting results contain M giants with 7 temperature subtypes from M0 to M6, M dwarfs with 18 temperature subtypes from K7.0 to M8.5 and 12 metallicity subclasses from dMr to usdMp. We cross-matched our M-type catalog with the 2MASS and WISE catalog to obtain infrared magnitude and colors. Adopting the distances derived from the parallaxes in \gaia{} DR2, the M_G vs. (G_bp-G_rp)_0 diagram shows that there are also early-type stars and white dwarf-M dwarf binaries included in our M type stars sample, with a contamination rate of about 4.6% for M giants and 0.48% for M dwarfs. We found that CaH spectral indices are an efficient selection criteria for carbon stars. A total of 289 carbon stars were identified from the M giants sample, and further confirmed by LAMOST spectra.