A Data-Driven M Dwarf Model and Detailed Abundances for $\sim$17,000 M Dwarfs in SDSS-V

TL;DR

This paper develops a data-driven model using The Cannon to accurately determine temperatures and detailed elemental abundances for approximately 17,000 M dwarfs from SDSS-V, overcoming previous modeling speed limitations.

Contribution

It introduces a new, efficient data-driven approach trained on binary star spectra to derive precise stellar parameters and abundances for a large sample of M dwarfs.

Findings

Model achieves median uncertainties of 13 K in temperature and 0.02 dex in abundances.

Successfully reproduces known abundance patterns and metallicity trends.

Provides detailed elemental abundances for 16,590 M dwarfs in SDSS-V.

Abstract

The cool temperatures of M dwarf atmospheres enable complex molecular chemistry, making robust characterization of M dwarf compositions a long-standing challenge. Recent modifications to spectral synthesis pipelines have enabled more accurate modeling of M dwarf atmospheres, but these methods are too slow for characterizing more than a handful of stars at a time. Data-driven methods such as The Cannon are viable alternatives, and can harness the information content of many M dwarfs from large spectroscopic surveys. Here, we train The Cannon on M dwarfs with FGK binary companions from the Sloan Digital Sky Survey-V/Milky Way Mapper (SDSS-V/MWM), with spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). The FGK-M pairs are assumed to be chemically homogeneous and span $-$0.56 $<$ [Fe/H] $<$ 0.31 dex. The resulting model is capable of inferring M dwarf $T_{\textrm{eff}}$ and elemental abundances for Fe, Mg, Al, Si, C, N, O, Ca, Ti, Cr, and Ni with median uncertainties of 13 K and 0.018$-$0.029 dex, respectively. We test the model by verifying that it reproduces reported abundance values of M dwarfs in open clusters and benchmark M dwarf datasets, as well as expected metallicity trends from stellar evolution. We apply the model to 16,590 M dwarfs in SDSS-V/MWM and provide their detailed abundances in our accompanying catalog.