RT Journal Article
T1 The CARMENES search for exoplanets around M dwarfs: variability of the HeI line at 10 830 Å
A1 Cortés Contreras, Miriam
A1 Montes Gutiérrez, David
AB The He I infrared (IR) triplet at 10 830 Å is known as an activity indicator in solar-type stars and has become a primary diagnostic in exoplanetary transmission spectroscopy. He I IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the He I triplet lines in a spectral time series of 319 M dwarf stars that was obtained with the CARMENES high-resolution optical and near-infrared spectrograph at Calar Alto. We detect He I IR line variability in 18% of our sample stars, all of which show Hα in emission. Therefore, we find detectable He I variability in 78% of the sub-sample of stars with Hα emission. Detectable variability is strongly concentrated in the latest spectral sub-types, where the He I lines during quiescence are typically weak. The fraction of stars with detectable He I variation remains lower than 10% for stars earlier than M3.0 V, while it exceeds 30% for the later spectral sub-types. Flares are accompanied by particularly pronounced line variations, including strongly broadened lines with red and blue asymmetries. However, we also find evidence for enhanced He I absorption, which is potentially associated with increased high-energy irradiation levels at flare onset. Generally, He I and Hα line variations tend to be correlated, with Hα being the most sensitive indicator in terms of pseudo-equivalent width variation. This makes the He I triplet a favourable target for planetary transmission spectroscopy.
PB EDP Sciencies
SN 0004-6361
YR 2020
FD 2020-08-10
LK https://hdl.handle.net/20.500.14352/6648
UL https://hdl.handle.net/20.500.14352/6648
LA eng
NO © ESO 2020. Artículo firmado por 26 autores. B.F. acknowledges funding by the DFG under Schm 1032/69-1. CARMENES is an instrument for the Centro Astronómico HispanoAlemán de Calar Alto (CAHA, Almería, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Científicas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciències de l’Espai, Institut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Centro de Astrobiología and Centro Astronómico Hispano-Alemán), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and DFG Research Unit FOR2544 “Blue Planets around Red Stars”, the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía.
NO the DFG
NO the German Max-Planck-Gesellschaft (MPG)
NO the Spanish Consejo Superior de Investigaciones Científicas (CSIC)
NO the European Union through FEDER/ERF FICTS-2011-02
NO the Max-Planck-Institut für Astronomie
NO Instituto de Astrofísica de Andalucía
NO Landessternwarte Königstuhl
NO Institut de Ciències de l’Espai
NO Institut für Astrophysik Göttingen
NO Universidad Complutense de Madrid
NO Thüringer Landessternwarte Tautenburg
NO Instituto de Astrofísica de Canarias
NO Hamburger Sternwarte
NO Centro de Astrobiología and Centro Astronómico Hispano-Alemán
NO España.  Ministerio de Economía
NO the German Science Foundation through the Major Research Instrumentation Programme
NO DFG Research Unit FOR2544 “Blue Planets around Red Stars”
NO the Klaus Tschira Stiftung
NO the states of Baden-Württemberg and Niedersachsen
NO the Junta de Andalucía, Spain
DS Docta Complutense
RD 27 abr 2024