The CARMENES search for exoplanets around M dwarfs Chromospheric modeling of M2-3V stars with PHOENIX

Autor: Juan Carlos Morales, Eike W. Guenther, Ansgar Reiners, Andreas Schweitzer, D. Galadí-Enríquez, M. Lafarga, Pedro J. Amado, Jose A. Caballero, M. Kürster, J. H. M. M. Schmitt, V. J. S. Béjar, D. Montes, E. N. Johnson, M. López del Fresno, Adrian Kaminski, Birgit Fuhrmeister, D. Hintz, V. M. Passegger, S. Czesla, A. Quirrenbach, I. Ribas, Mathias Zechmeister, Walter Seifert, S. Dreizler, Guillem Anglada-Escudé, Sandra V. Jeffers, F. F. Bauer, Peter H. Hauschildt, M. Cortés-Contreras
Přispěvatelé: German Research Foundation, Max Planck Society, Consejo Superior de Investigaciones Científicas (España), European Commission, Ministerio de Ciencia e Innovación (España)
Rok vydání: 2019
Předmět:
Zdroj: E-Prints Complutense. Archivo Institucional de la UCM
instname
Astronomy and Astrophysics
E-Prints Complutense: Archivo Institucional de la UCM
Universidad Complutense de Madrid
Digital.CSIC. Repositorio Institucional del CSIC
Popis: Chromospheric modeling of observed differences in stellar activity lines is imperative to fully understand the upper atmospheres of late-type stars. We present one-dimensional parametrized chromosphere models computed with the atmosphere code PHOENIX using an underlying photosphere of 3500 K. The aim of this work is to model chromospheric lines of a sample of 50 M2-3 dwarfs observed in the framework of the CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, exoplanet survey. The spectral comparison between observed data and models is performed in the chromospheric lines of Na?raquo; I D2, Hα, and the bluest Ca?raquo; II infrared triplet line to obtain best-fit models for each star in the sample. We find that for inactive stars a single model with a VAL C-like temperature structure is sufficient to describe simultaneously all three lines adequately. Active stars are rather modeled by a combination of an inactive and an active model, also giving the filling factors of inactive and active regions. Moreover, the fitting of linear combinations on variable stars yields relationships between filling factors and activity states, indicating that more active phases are coupled to a larger portion of active regions on the surface of the star. © ESO 2019.
D.H. acknowledges funding by the DLR under DLR 50 OR1701. B.F. acknowledges funding by the DFG under Cz 222/1-1 and Schm 1032/69-1. S.C. acknowledges support through DFG projects SCH 1382/2-1 and SCHM 1032/66-1. CARMENES is an instrument for the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciencies de l'Espai, Institut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenburg, Instituto de Astrofisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Aleman), with additional contributions by the Spanish Ministry of Science [through projects AYA2016-79425-C3-1/2/3-P, ESP2016-80435-C2-1-R, AYA2015-69350-C3-2-P, and AYA2018-84089], 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-Wurttemberg and Niedersachsen, and by the Junta de Andalucia.
Databáze: OpenAIRE
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