Constraining atmospheric parameters and surface magnetic fields with $\text{ZeeTurbo}$: an application to SPIRou spectra

Abstract

We report first results on a method aimed at simultaneously characterising atmospheric parameters and magnetic properties of M dwarfs from high-resolution nIR spectra recorded with SPIRou in the framework of the SPIRou Legacy Survey. Our analysis relies on fitting synthetic spectra computed from MARCS model atmospheres to selected spectral lines, both sensitive and insensitive to magnetic fields. We introduce a new code, $\text{ZeeTurbo}$, obtained by including the Zeeman effect and polarised radiative transfer capabilities to $\text{Turbospectrum}$. We compute a grid of synthetic spectra with $\text{ZeeTurbo}$ for different magnetic field strengths and develop a process to simultaneously constrain $T_{\mathrm{eff}}$, $\log g$, [M/H], [$\alpha$/Fe] and the average surface magnetic flux. In this paper, we present our approach and assess its performance using simulations, before applying it to six targets observed in the context of the SPIRou Legacy Survey (SLS), namely AU Mic, EV Lac, AD Leo, CN Leo, PM J18482+0741, and DS Leo. Our method allows us to retrieve atmospheric parameters in good agreement with the literature, and simultaneously yields surface magnetic fluxes in the range 2-4 kG with a typical precision of 0.05 kG, in agreement with literature estimates, and consistent with the saturated dynamo regime in which most of these stars are.

17 pages plus supplementary material. Accepted for publication in MNRAS

References in corpus (25)

• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Large-scale magnetic topologies of early M dwarfs
• CH in stellar atmospheres: an extensive linelist
• Trumpeting M Dwarfs with CONCH-SHELL: a Catalog of Nearby Cool Host-Stars for Habitable ExopLanets and Life
• The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars
• A planet within the debris disk around the pre-main-sequence star AU Microscopii
• The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres
• Line lists for the A2PI-X2Sigma+ (red) and {B2Sigma+-X2Sigma} (violet) Systems of CN, 13C14N, and 12C15N, and Application to Astronomical Spectra
• SPIRou: nIR velocimetry & spectropolarimetry at the CFHT
• ExoMol molecular line lists V: The ro-vibrational spectra of NaCl and KCl
• Magnetic fields of M dwarfs
• Revisiting Proxima with ESPRESSO
• The CARMENES search for exoplanets around M dwarfs -- Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multiwavelength range modeling of activity insensitive lines
• APERO: A PipelinE to Reduce Observations -- Demonstration with SPIRou
• Investigating the young AU~Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass
• HADES RV Programme with HARPS-N at TNG XII. The abundance signature of M dwarf stars with planets
• Hyperfine Splitting in the VALD Database of Spectral-line Parameters
• ExoMol line lists XXIV: A new hot line list for silicon monohydride, SiH
• One year of AU Mic with HARPS: II -- stellar activity and star-planet interaction
• Spin-orbit alignment and magnetic activity in the young planetary system AU Mic
• Estimating the atmospheric properties of 44 M dwarfs from SPIRou spectra
• Magnetic fields of intermediate mass T Tauri stars
• Estimating fundamental parameters of nearby M dwarfs from SPIRou spectra
• The anomalous atmospheric structure of the strongly magnetic Ap star HD166473

Cited by in corpus (1)

• The magnetic field and multiple planets of the young dwarf AU~Mic