Magnetic field and velocity of mid M dwarfs : J/MNRAS/390/567


Authors : Morin J. orcid , Donati J.-F., Petit P. (hide) , Donati J.-F., Petit P. et..al

Bibcode : 2008MNRAS.390..567M (ADS) (Simbad) (Objects) (hide)

CDS Keywords : Stars, M-type; Magnetic fields
UAT : M stars, Magnetic fields

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Inserted into VizieR : 05-Jul-2010
Last modification : 07-Jul-2024

Large-scale magnetic topologies of mid M dwarfs. (2008)

Keywords : stars magnetic field - stars: low-mass, brown dwarfs - stars: rotation - techniques: spectroscopy - techniques: polarimetry

Abstract:We present in this paper, the first results of a spectropolarimetric analysis of a small sample (~20) of active stars ranging from spectral type M0 to M8, which are either fully convective or possess a very small radiative core. This study aims at providing new constraints on dynamo processes in fully convective stars. This paper focuses on ve stars of spectral type ~M4, i.e. with masses close to the full convection threshold (0.35M_{sun}_), and with short rotational periods. Tomographic imaging techniques allow us to reconstruct the surface magnetic topologies from the rotationally modulated time-series of circularly polarized profiles. We find that all stars host mainly axisymmetric large-scale poloidal fields. Three stars were observed at ...(more)
Abstract: (hide)
We have collected 107 pairs of Stokes I (unpolarised) and V (circularly polarised) spectra with the twin instruments ESPaDOnS at CFHT (2003ASPC..307...41D) and NARVAL at TBL between January 2006 and February 2008. All spectra were reduced using the Libre-Esprit pipeline, and the mean I and V line profiles were extracted using the Least-Squares Deconvolution (LSD) technique (1997MNRAS.291..658D). The star V374 Peg (2008MNRAS.384...77M) is also included in the discussion and in table1.dat.
Julien Morin, jmorin(at)cp.dias.ie

                
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