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Título:
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The CARMENES search for exoplanets around M dwarfs. The He I triplet at 10830 Å across the M dwarf sequence
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Autores:
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Sanz Forcada, J. ;
Caballero, J. A. ;
Cortés Contreras, Miriam ;
Montes Gutiérrez, David
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Tipo de documento:
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texto impreso
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Editorial:
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EDP Sciencies, 2019-11-25
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física: Astrofísica
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Materia = Ciencias: Física: Astronomía
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Tipo = Artículo
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Resumen:
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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 (L_(X)/L_(bol)
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En línea:
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https://eprints.ucm.es/id/eprint/63906/1/davidmontes116libre.pdf
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