Stellar parameters of early M dwarfs from ratios of spectral features at optical wavelengths

Abstract

(Abridged) Low-mass stars have been recognised as promising targets in the search for rocky, small planets with the potential of supporting life. Doppler search programmes using high-resolution spectrographs like HARPS or HARPS-N are providing huge quantities of optical spectra of M dwarfs. We aim to calibrate empirical relationships to determine stellar parameters for early M dwarfs (spectral types M0-M4.5) using the same spectra that are used for the radial velocity determinations. Our methodology consists in the use of ratios of pseudo equivalent widths of spectral features as a temperature diagnostic. Stars with effective temperatures obtained from interferometric estimates of their radii are used as calibrators. Empirical calibrations for the spectral type are also provided. Combinations of features and ratios of features are used to derive calibrations for the stellar metallicity. Our methods are then applied to a large sample of M dwarfs that are being observed in the framework of the HARPS search for extrasolar planets.The derived temperatures and metallicities are used together with photometric estimates of mass, radius, and surface gravity to calibrate empirical relationships for these parameters. A total of 112 temperature sensitive ratios have been calibrated over the range 3100-3950 K, providing Teff values with typical uncertainties of the order of 70 K. Eighty-two ratios of pseudo equivalent widths of features were calibrated to derive spectral types. Regarding stellar metallicity, 696 combinations of pseudo equivalent widths of individual features and temperature-sensitive ratios have been calibrated, over the metallicity range from -0.54 to +0.24 dex, with estimated uncertainties in the range of 0.07-0.10 dex. We provide our own empirical calibrations for stellar mass, radius, and surface gravity.

arXiv commentAccepted for publication by Astronomy and Astrophysics

References in corpus (40)

• The Dartmouth Stellar Evolution Database
• Color Transformations for the 2MASS Second Incremental Data Release
• Models of Stars, Brown Dwarfs and Exoplanets
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• The Occurrence Rate of Small Planets around Small Stars
• Stellar Diameters and Temperatures II. Main Sequence K & M Stars
• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
• The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog I: Data
• Trumpeting M Dwarfs with CONCH-SHELL: a Catalog of Nearby Cool Host-Stars for Habitable ExopLanets and Life
• A Spectroscopic Catalog of the Brightest (J<9) M Dwarfs in the Northern Sky
• Near-infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs
• Spectro-Thermometry of M dwarfs and their candidate planets: too hot, too cool, or just right?
• Revised metallicity classes for low-mass stars: dwarfs (dM), subdwarfs (sdM), extreme subdwarfs (esdM), and ultra subdwarfs (usdM)
• M dwarfs: effective temperatures, radii and metallicities
• Prospecting in late-type dwarfs: a calibration of infrared and visible spectroscopic metallicities of late-K and M dwarfs spanning 1.5 dex
• On the Metal-Richness of M Dwarfs with Planets
• First radius measurements of very low mass stars with the VLTI
• Accurate fundamental parameters for Lower Main Sequence Stars
• The M Dwarf GJ 436 and its Neptune-Mass Planet
• Stellar Diameters and Temperatures V. Eleven Newly Characterized Exoplanet Host Stars
• The GAPS programme with HARPS-N at TNG. I: Observations of the Rossiter-McLaughlin effect and characterisation of the transiting system Qatar-1
• HATS-6b: A Warm Saturn Transiting an Early M Dwarf Star, and a Set of Empirical Relations for Characterizing K and M Dwarf Planet Hosts
• Atmospheres from very low-mass stars to extrasolar planets
• A Physically-Motivated Photometric Calibration of M Dwarf Metallicity
• Metallicity measurements using atomic lines in M and K dwarf stars
• Metallicity of M dwarfs IV. A high-precision [Fe/H] and Teff technique from high-resolution optical spectra for M dwarfs
• An H-band Spectroscopic Metallicity Calibration for M Dwarfs
• Metallicities of M Dwarf Planet Hosts from Spectral Synthesis
• An empirical calibration to estimate cool dwarf fundamental parameters from H-band spectra
• High precision effective temperatures for 181 F--K dwarfs from line-depth ratios
• M-dwarf metallicities - A high-resolution spectroscopic study in the near infrared
• A high resolution spectroscopic atlas of M subdwarfs - Effective temperature and metallicity
• Refined Metallicity Indices for M Dwarfs Using the SLoWPoKES Catalog of Wide, Low-mass Binaries
• An Effective temperature calibration for solar type stars using equivalent width ratios - A fast and easy spectroscopic temperature estimation
• New solar twins and the metallicity and temperature scales of the Geneva Copenhagen Survey
• Solar analogues and Solar twins in the HARPS archive
• Spectroscopic study of solar twins and analogues
• The APACHE Project

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• ODUSSEAS: Upgraded version with new reference scale and parameter determinations for 82 planet-host M dwarf stars in SWEET-Cat
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• Metallicities in M dwarfs: Investigating different determination techniques