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Large-scale magnetic topologies of mid M dwarfs
- Source :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, 2008, 390, pp.567-581. ⟨10.1111/J.1365-2966.2008.13809.X⟩, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2008, 390, pp.567-581. ⟨10.1111/J.1365-2966.2008.13809.X⟩
- Publication Year :
- 2008
- Publisher :
- HAL CCSD, 2008.
-
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. The present paper focuses on 5 stars of spectral type ~M4, i.e. with masses close to the full convection threshold (~ 0.35 Msun), and with short rotational periods. Tomographic imaging techniques allow us to reconstruct the surface magnetic topologies from the rotationally modulated time-series of circularly polarised profiles. We fnd that all stars host mainly axisymmetric large-scale poloidal fields. Three stars were observed at two different epochs separated by ~1 yr; we find the magnetic topologies to be globally stable on this timescale. We also provide an accurate estimation of the rotational period of all stars, thus allowing us to start studying how rotation impacts the large-scale magnetic field.<br />Comment: 17 pages, 14 figures, accepted for publication in MNRAS
- Subjects :
- 010504 meteorology & atmospheric sciences
[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
Astrophysics (astro-ph)
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
01 natural sciences
techniques: polarimetric
Space and Planetary Science
stars: low-mass
stars: rotation
0103 physical sciences
stars: activity
stars: magnetic fields
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
010303 astronomy & astrophysics
0105 earth and related environmental sciences
brown dwarfs
Subjects
Details
- Language :
- English
- ISSN :
- 00358711 and 13652966
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, 2008, 390, pp.567-581. ⟨10.1111/J.1365-2966.2008.13809.X⟩, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2008, 390, pp.567-581. ⟨10.1111/J.1365-2966.2008.13809.X⟩
- Accession number :
- edsair.doi.dedup.....284fcd98f723d8487de81217f070b7c3