Magnetic fields in M dwarfs from the CARMENES survey
Context: M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, butthe link between the magnetic fields and underlying dynamo mechanisms, rotation, and activity still lacks a consistent picture.Aims.In this work we measure magnetic fields fr...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
29 April 2019
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| In: |
Astronomy and astrophysics
Year: 2019, Volume: 626 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201935315 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1051/0004-6361/201935315
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| Author Notes: | D. Shulyak, A. Reiners, E. Nagel, L. Tal-Or, J.A. Caballero, M. Zechmeister, V.J.S. Béjar, M. Cortés-Contreras, E.L. Martin, A. Kaminski, I. Ribas, A. Quirrenbach, P.J. Amado, G. Anglada-Escudé, F.F. Bauer, S. Dreizler, E.W. Guenther, T. Henning, S.V. Jeffers, M. Kürster, M. Lafarga, J.C. Morales, and S. Pedraz |
| Summary: | Context: M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, butthe link between the magnetic fields and underlying dynamo mechanisms, rotation, and activity still lacks a consistent picture.Aims.In this work we measure magnetic fields from the high-resolution near-infrared spectra taken with the CARMENES radial-velocity planet survey in a sample of 29 active M dwarfs and compare our results against stellar parameters.Methods.We use the state-of-the-art radiative transfer code to measure total magnetic flux densities from the Zeeman broadening ofspectral lines and filling factors.Results: We detect strong kG magnetic fields in all our targets. In 16 stars the magnetic fields were measured for the first time. Ourmeasurements are consistent with the magnetic field saturation in stars with rotation periodsP<4 d. The analysis of the magneticfilling factors reveal two different patterns of either very smooth distribution or a more patchy one, which can be connected to thedynamo state of the stars and/or stellar mass.Conclusions: Our measurements extend the list of M dwarfs with strong surface magnetic fields. They also allow us to better constrainthe interplay between the magnetic energy, stellar rotation, and underlying dynamo action. The high spectral resolution and obser-vations at near-infrared wavelengths are the beneficial capabilities of the CARMENES instrument that allow us to address importantquestions about the stellar magnetism. |
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| Item Description: | Submitted on 29 April 2019 Gesehen am 15.01.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201935315 |