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The CARMENES search for exoplanets around M dwarfs: the He I triplet at 10830 Å across the M dwarf sequence

The He I infrared (IR) triplet at 10 830 Å is an important activity indicator for the Sun and in solar-type stars, however, it has rarely been studied in relation to M dwarfs to date. In this study, we use the time-averaged spectra of 319 single stars with spectral types ranging from M0.0 V to M9.0...

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Hauptverfasser: Fuhrmeister, Birgit (VerfasserIn) , Czesla, S. (VerfasserIn) , Hildebrandt, L. (VerfasserIn) , Nagel, E. (VerfasserIn) , Schmitt, J. H. M. M. (VerfasserIn) , Hintz, D. (VerfasserIn) , Johnson, E. N. (VerfasserIn) , Sanz-Forcada, J. (VerfasserIn) , Schöfer, P. (VerfasserIn) , Jeffers, S. V. (VerfasserIn) , Caballero, J. A. (VerfasserIn) , Zechmeister, M. (VerfasserIn) , Reiners, A. (VerfasserIn) , Ribas, I. (VerfasserIn) , Amado, P. J. (VerfasserIn) , Quirrenbach, Andreas (VerfasserIn) , Bauer, F. F. (VerfasserIn) , Béjar, V. J. S. (VerfasserIn) , Cortés-Contreras, M. (VerfasserIn) , Díez-Alonso, E. (VerfasserIn) , Dreizler, S. (VerfasserIn) , Galadí-Enríquez, D. (VerfasserIn) , Guenther, E. W. (VerfasserIn) , Kaminski, Adrian (VerfasserIn) , Kürster, M. (VerfasserIn) , Lafarga, M. (VerfasserIn) , Montes, D. (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 25 November 2019
In: Astronomy and astrophysics
Year: 2019, Jahrgang: 632
ISSN:1432-0746
DOI:10.1051/0004-6361/201936193
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1051/0004-6361/201936193
Verlag, lizenzpflichtig, Volltext: https://www.aanda.org/articles/aa/abs/2019/12/aa36193-19/aa36193-19.html
Volltext
Verfasserangaben:B. Fuhrmeister, S. Czesla, L. Hildebrandt, E. Nagel, J.H.M.M. Schmitt, D. Hintz, E.N. Johnson, J. Sanz-Forcada, P. Schöfer, S.V. Jeffers, J.A. Caballero, M. Zechmeister, A. Reiners, I. Ribas, P.J. Amado, A. Quirrenbach, F.F. Bauer, V.J.S. Béjar, M. Cortés-Contreras, E. Díez-Alonso, S. Dreizler, D. Galadí-Enríquez, E.W. Guenther, A. Kaminski, M. Kürster, M. Lafarga, and D. Montes
Beschreibung
Zusammenfassung:The He I infrared (IR) triplet at 10 830 Å is an important activity indicator for the Sun and in solar-type stars, however, it has rarely been studied in relation to M dwarfs to date. In this study, we use the time-averaged spectra of 319 single stars with spectral types ranging from M0.0 V to M9.0 V obtained with the CARMENES high resolution optical and near-infrared spectrograph at Calar Alto to study the properties of the He I IR triplet lines. In quiescence, we find the triplet in absorption with a decrease of the measured pseudo equivalent width (pEW) towards later sub-types. For stars later than M5.0 V, the He I triplet becomes undetectable in our study. This dependence on effective temperature may be related to a change in chromospheric conditions along the M dwarf sequence. When an emission in the triplet is observed, we attribute it to flaring. The absence of emission during quiescence is consistent with line formation by photo-ionisation and recombination, while flare emission may be caused by collisions within dense material. The He I triplet tends to increase in depth according to increasing activity levels, ultimately becoming filled in; however, we do not find a correlation between the pEW(He IR) and X-ray properties. This behaviour may be attributed to the absence of very inactive stars (<i>L<i/><sub>X<sub/>∕<i>L<i/><sub>bol<sub/> < −5.5) in our sample or to the complex behaviour with regard to increasing depth and filling in.
Beschreibung:Gesehen am 06.03.2020
Beschreibung:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/201936193

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