Building reliable models of M dwarf chromospheres: The impact of the usual assumptions

We study different approximations usually made to simplify the calculation of chromospheric models of M dwarf stars. The approximations we discuss in details are: the assumption that the minority species are in LTE, the omission of the contribution of numerous atomic and molecular lines (line blanke...

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Detalles Bibliográficos
Autores principales: Falchi, A., Mauas, P.J.D.
Formato: JOUR
Materias:
Stars: atmospheres
Stars: chromosphere
Stars: late-type
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00046361_v336_n1_p281_Falchi
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00046361_v336_n1_p281_Falchi
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spelling todo:paper_00046361_v336_n1_p281_Falchi2023-10-03T13:59:52Z Building reliable models of M dwarf chromospheres: The impact of the usual assumptions Falchi, A. Mauas, P.J.D. Stars: atmospheres Stars: chromosphere Stars: late-type We study different approximations usually made to simplify the calculation of chromospheric models of M dwarf stars. The approximations we discuss in details are: the assumption that the minority species are in LTE, the omission of the contribution of numerous atomic and molecular lines (line blanketing) to the opacity, and the Complete Frequency Redistribution for the Lyα line. We consider a "cold" chromospheric model corresponding to a low activity dM star and a "hot" one corresponding to a very active dMe star. We find that the assumptions under study affect more strongly the cold than the hot model. In particular the approximation of Complete Frequency Redistribution in the Lyα line, through the statistical equilibrium and ionization equilibrium equation, changes the electron density in the high chromosphere and strongly affects other line profiles. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046361_v336_n1_p281_Falchi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Stars: atmospheres
Stars: chromosphere
Stars: late-type
spellingShingle Stars: atmospheres
Stars: chromosphere
Stars: late-type
Falchi, A.
Mauas, P.J.D.
Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
topic_facet Stars: atmospheres
Stars: chromosphere
Stars: late-type
description We study different approximations usually made to simplify the calculation of chromospheric models of M dwarf stars. The approximations we discuss in details are: the assumption that the minority species are in LTE, the omission of the contribution of numerous atomic and molecular lines (line blanketing) to the opacity, and the Complete Frequency Redistribution for the Lyα line. We consider a "cold" chromospheric model corresponding to a low activity dM star and a "hot" one corresponding to a very active dMe star. We find that the assumptions under study affect more strongly the cold than the hot model. In particular the approximation of Complete Frequency Redistribution in the Lyα line, through the statistical equilibrium and ionization equilibrium equation, changes the electron density in the high chromosphere and strongly affects other line profiles.
format JOUR
author Falchi, A.
Mauas, P.J.D.
author_facet Falchi, A.
Mauas, P.J.D.
author_sort Falchi, A.
title Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
title_short Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
title_full Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
title_fullStr Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
title_full_unstemmed Building reliable models of M dwarf chromospheres: The impact of the usual assumptions
title_sort building reliable models of m dwarf chromospheres: the impact of the usual assumptions
url http://hdl.handle.net/20.500.12110/paper_00046361_v336_n1_p281_Falchi
work_keys_str_mv AT falchia buildingreliablemodelsofmdwarfchromospherestheimpactoftheusualassumptions
AT mauaspjd buildingreliablemodelsofmdwarfchromospherestheimpactoftheusualassumptions
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