Estimating the atmospheric properties of 44 M dwarfs from SPIRou spectra

• Published in: Monthly notices of the Royal Astronomical Society Vol. 516; no. 3; pp. 3802 - 3820
• Main Authors: Cristofari, P I, Donati, J-F, Masseron, T, Fouqué, P, Moutou, C, Carmona, A, Artigau, E, Martioli, E, Hébrard, G, Gaidos, E, Delfosse, X
• Format: Journal Article
• Language: English
• Published: Oxford University Press (OUP): Policy P - Oxford Open Option A 20.09.2022
• Subjects: Sciences of the Universe
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stac2364

ABSTRACT We describe advances on a method designed to derive accurate parameters of M dwarfs. Our analysis consists in comparing high-resolution infrared spectra acquired with the near-infrared spectro-polarimeter SPIRou to synthetic spectra computed from MARCS model atmospheres, in order to derive the effective temperature (Teff), surface gravity (log g), metallicity ($\rm {[M/H]}$), and alpha-enhancement ($\rm {[\alpha /Fe]}$) of 44 M dwarfs monitored within the SPIRou Legacy Survey (SLS). Relying on 12 of these stars, we calibrated our method by refining our selection of well-modelled stellar lines, and adjusted the line list parameters to improve the fit when necessary. Our retrieved Teff, log g, and $\rm {[M/H]}$ are in good agreement with literature values, with dispersions of the order of 50 K in Teff and 0.1 dex in log g and $\rm {[M/H]}$. We report that fitting $\rm {[\alpha /Fe]}$ has an impact on the derivation of the other stellar parameters, motivating us to extend our fitting procedure to this additional parameter. We find that our retrieved $\rm {[\alpha /Fe]}$ are compatible with those expected from empirical relations derived in other studies.