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

Research output: Contribution to journalArticle

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.

Details

Authors
  • 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 Wanderley
  • And 1 others
  • Olga Zamora
Organisations
External organisations
  • Federal University of Sergipe
  • National Observatory Brazil
  • University of Arizona
  • National Optical Astronomy Observatory
  • Instituto de Astrofísica de Canarias
  • University of La Laguna (ULL)
  • Western Washington University
  • New Mexico State University
  • Ohio State University
  • Malmö University
  • Pennsylvania State University
  • University of Virginia
  • University of Texas at Austin
  • Vanderbilt University
  • Carleton College
  • Carnegie Observatories
  • University of California, San Diego
  • University of Tarapacá
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology
Original languageEnglish
Article number133
JournalAstrophysical Journal
Volume890
Issue number2
Publication statusPublished - 2020 Feb 20
Publication categoryResearch
Peer-reviewedYes