Stellar Characterization of M Dwarfs from the APOGEE Survey: A Calibrator Sample for M-dwarf Metallicities

Diogo Souto, Katia Cunha, Verne V. Smith, C. Allende Prieto, Adam Burgasser, Kevin Covey, D. A. García-Hernández, Jon A. Holtzman, Jennifer A. Johnson, Henrik Jönsson, Suvrath Mahadevan, Steven R. Majewski, Thomas Masseron, Matthew Shetrone, Bárbara Rojas-Ayala, Jennifer Sobeck, Keivan G. Stassun, Ryan Terrien, Johanna Teske, Fábio WanderleyOlga Zamora

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We present spectroscopic determinations of the effective temperatures, surface gravities, and metallicities for 21 M dwarfs observed at high resolution (R ∼ 22,500) in the H band as part of the Sloan Digital Sky Survey (SDSS)-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. The atmospheric parameters and metallicities are derived from spectral syntheses with 1D LTE plane-parallel MARCS models and the APOGEE atomic/molecular line list, together with up-to-date H2O and FeH molecular line lists. Our sample range in T eff from ∼3200 to 3800 K, where 11 stars are in binary systems with a warmer (FGK) primary, while the other 10 M dwarfs have interferometric radii in the literature. We define an MKS-radius calibration based on our M-dwarf radii derived from the detailed analysis of APOGEE spectra and Gaia DR2 distances, as well as a mass-radius relation using the spectroscopically derived surface gravities. A comparison of the derived radii with interferometric values from the literature finds that the spectroscopic radii are slightly offset toward smaller values, with Δ = -0.01 ± 0.02 R∗/R o-. In addition, the derived M-dwarf masses based upon the radii and surface gravities tend to be slightly smaller (by ∼5%-10%) than masses derived for M-dwarf members of eclipsing binary systems for a given stellar radius. The metallicities derived for the 11 M dwarfs in binary systems, compared to metallicities obtained for their hotter FGK main-sequence primary stars from the literature, show excellent agreement, with a mean difference of [Fe/H](M dwarf - FGK primary) = +0.04 ± 0.18 dex, confirming the APOGEE metallicity scale derived here for M dwarfs.

Original languageEnglish (US)
Article number133
JournalAstrophysical Journal
Volume890
Issue number2
DOIs
StatePublished - Feb 20 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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