Metallicity of M dwarfs. IV. A high-precision [Fe/H] and T_eff technique from high-resolution optical spectra for M dwarfs

V. Neves (1) , X. Bonfils (1) , N. C. Santos , X. Delfosse (1) , T. Forveille (1) , F. Allard (2) , S. Udry

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
2 CRAL - Centre de Recherche Astrophysique de Lyon

Aims: In this work we develop a technique to obtain high precision determinations of both metallicity and effective temperature of M dwarfs in the optical.
Methods: A new method is presented that makes use of the information of 4104 lines in the 530-690 nm spectral region. It consists in the measurement of pseudo equivalent widths and their correlation with established scales of [Fe/H] and T_eff.
Results: Our technique achieves a rms of 0.08 ± 0.01 for [Fe/H], 91 ± 13 K for T_eff, and is valid in the (-0.85,0.26 dex), (2800, 4100 K), and (M0.0, M5.0) intervals for [Fe/H], T_eff and spectral type respectively. We also calculated the RMSE_V which estimates uncertainties of the order of 0.12 dex for the metallicity and of 293 K for the effective temperature. The technique has an activity limit and should only be used for stars with log L_Hα/L_bol< - 4.0.

Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla Observatory under programme ID 072.C-0488(E)Our method is available online at http://www.astro.up.pt/resources/mcalTables 1, 2, 4, 8 are available in electronic form at http://www.aanda.org

Keywords: Astrophysics - Solar and Stellar Astrophysics; methods: data analysis; stars: low-mass; stars: late-type; stars: fundamental parameters; stars: atmospheres

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

V. Neves, X. Bonfils, N. C. Santos, X. Delfosse, T. Forveille, et al.. Metallicity of M dwarfs. IV. A high-precision [Fe/H] and T_eff technique from high-resolution optical spectra for M dwarfs. Astronomy and Astrophysics - A&A, 2014, 568, ⟨10.1051/0004-6361/201424139⟩. ⟨insu-03618548⟩