# An empirical template library of stellar spectra for a wide range of spectral classes, luminosity classes, and metallicities using SDSS BOSS spectra

## TL;DR

This paper introduces an extensive empirical library of stellar spectra from SDSS BOSS, covering a wide range of spectral types, luminosity classes, and metallicities, along with a tool for spectral classification.

## Contribution

The creation of the first empirical stellar spectral library with comprehensive temperature and metallicity coverage, including M8 metallicity bins, and a spectral classification tool.

## Key findings

- Identified metallicity and gravity trends in color space.
- Extended M dwarf metallicity coverage to M8.
- Provided a spectral classification tool for automated analysis.

## Abstract

We present a library of empirical stellar spectra created using spectra from the Sloan Digital Sky Survey's Baryon Oscillation Spectroscopic Survey (BOSS). The templates cover spectral types O5 through L3, are binned by metallicity from -2.0 dex through +1.0 dex and are separated into main sequence (dwarf) stars and giant stars. With recently developed M dwarf metallicity indicators, we are able to extend the metallicity bins down through the spectral subtype M8, making this the first empirical library with this degree of temperature \emph{and} metallicity coverage. The wavelength coverage for the templates is from 3650 Angstroms through 10200 Angstroms at a resolution better than R~2000. Using the templates, we identify trends in color space with metallicity and surface gravity, which will be useful for analyzing large data sets from upcoming missions like LSST. Along with the templates, we are releasing a code for automatically (and/or visually) identifying the spectral type and metallicity of a star.