Magnetic fields in M dwarfs from the CARMENES survey
Shulyak, Denis (Göttingen Universität. Institut fur Astrophysik (Alemanya))
Reiners, Ansgar (Max-Planck-Institute fur Sonnensystemforschung (Alemanya))
Nagel, Evangelos (Hamburger Sternwarte (Hamburg, Alemanya))
Tal-Or, Lev (Tel Aviv University. Department of Geophysics (Israel))
Caballero, Jose A. (Centro de Astrobiología (Madrid))
Zechmeister, Mathias (Göttingen Universität. Institut fur Astrophysik (Alemanya))
Sánchez Béjar, Víctor J. (Instituto de Astrofísica de Canarias (Tenerife, Illa de les Canàries))
Cortés Contreras, Miriam (Centro de Astrobiología (Madrid))
Martin, Eduardo L. (Centro de Astrobiología (Madrid))
Kaminski, Adrian (Universität Heidelberg. Zentrum für Astronomie)
Ribas, Ignasi (Institut de Ciències de l'Espai (Barcelona))
Quirrenbach, Andreas (Universität Heidelberg. Zentrum für Astronomie)
Amado, Pedro J. (Instituto de Astrofísica de Andalucía (Granada))
Anglada-Escudé, Guillem (Queen Mary University of London (Regne Unit))
Bauer, Florian F. (Instituto de Astrofísica de Andalucía (Granada))
Dreizler, Stefan (Göttingen Universität. Institut fur Astrophysik (Alemanya))
Guenther, Eike W. (Thüringer Landessternwarte Tautenburg (Alemanya))
Henning, Thomas (Max-Planck-Institut fur Astronomie (Alemanya))
Jeffers, Sandra V. (Göttingen Universität. Institut fur Astrophysik (Alemanya))
Kürster, Martin (Max-Planck-Institut fur Astronomie (Alemanya))
Lafarga, Marina (Institut de Ciències de l'Espai (Barcelona))
Montes, David (Universidad Complutense de Madrid. Departamento de Física de la Tierra y Astrofísica (Madrid))
Morales, Juan Carlos (Institut de Ciències de l'Espai (Barcelona))
Pedraz, Santos (Centro Astronómico Hispano-Alemán (Almeria))

Data:	2019
Resum:	Context. M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, but we are still lacking a consistent picture of the link between the magnetic fields and underlying dynamo mechanisms, rotation, and activity. Aims. In this work we aim to 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 used the state-of-The-Art radiative transfer code to measure total magnetic flux densities from the Zeeman broadening of spectral 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. Our measurements are consistent with the magnetic field saturation in stars with rotation periods P < 4 d. The analysis of the magnetic filling factors reveal two different patterns of either very smooth distribution or a more patchy one, which can be connected to the dynamo 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 constrain the interplay between the magnetic energy, stellar rotation, and underlying dynamo action. The high spectral resolution and observations at near-infrared wavelengths are the beneficial capabilities of the CARMENES instrument that allow us to address important questions about the stellar magnetism.
Ajuts:	Ministerio de Economía y Competitividad FICTS-2011-02
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Stars: low-mass ; Stars: magnetic field ; Stars: rotation ; Stars: atmospheres
Publicat a:	Astronomy & astrophysics, Vol. 626 (June 2019) , art. A86, ISSN 1432-0746

DOI: 10.1051/0004-6361/201935315

24 p, 17.4 MB

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