The Influence of Chromospheric Activity on Line Formation

One of the primary sources of stellar spectral variability is magnetic activity. While our current understanding of chromospheric activity is largely derived from specific lines sensitive to chromospheric heating, such as the Ca ii H and K doublet, previous observational studies have shown that othe...

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Main Authors: Mariela C. Vieytes, Lily L. Zhao, Megan Bedell
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/adb0c6
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author Mariela C. Vieytes
Lily L. Zhao
Megan Bedell
author_facet Mariela C. Vieytes
Lily L. Zhao
Megan Bedell
author_sort Mariela C. Vieytes
collection DOAJ
description One of the primary sources of stellar spectral variability is magnetic activity. While our current understanding of chromospheric activity is largely derived from specific lines sensitive to chromospheric heating, such as the Ca ii H and K doublet, previous observational studies have shown that other spectral lines are also affected. To investigate the influence of activity on line formation in greater detail, we constructed a set of stellar models for hypothetical G2 dwarf stars with varying levels of activity and calculated their synthetic spectra. A comparison of these spectra revealed two spectral regions most significantly impacted by activity: approximately 3300–4400 Å and 5250–5500 Å. By calculating the total contribution function of the lines, we determined that the emergence of a secondary chromospheric contribution to line formation is the primary mechanism driving these changes. Based on our calculations and analysis, we compiled a list of transition lines and their corresponding changes due to chromospheric activity. This list could serve as a valuable tool for selecting spectral lines applicable to a wide range of astrophysical studies.
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spelling doaj-art-65770f95d4cf4ff49ea9caee46e8f9f52025-08-20T03:01:32ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-019811410.3847/1538-4357/adb0c6The Influence of Chromospheric Activity on Line FormationMariela C. Vieytes0https://orcid.org/0000-0003-4615-8746Lily L. Zhao1https://orcid.org/0000-0002-3852-3590Megan Bedell2https://orcid.org/0000-0001-9907-7742Instituto de Astronomía y Física del Espacio , (IAFE, CONICET-UBA) Buenos Aires, Argentina ; mvieytes@untref.edu.ar; Departamento de Ciencia y Tecnología , UNTREF, Buenos Aires, Argentina; Center for Computational Astrophysics (CCA), Flatiron Institute , New York, NY 10010, USACenter for Computational Astrophysics (CCA), Flatiron Institute , New York, NY 10010, USA; Department of Astronomy & Astrophysics, University of Chicago , Chicago, IL 60637, USACenter for Computational Astrophysics (CCA), Flatiron Institute , New York, NY 10010, USAOne of the primary sources of stellar spectral variability is magnetic activity. While our current understanding of chromospheric activity is largely derived from specific lines sensitive to chromospheric heating, such as the Ca ii H and K doublet, previous observational studies have shown that other spectral lines are also affected. To investigate the influence of activity on line formation in greater detail, we constructed a set of stellar models for hypothetical G2 dwarf stars with varying levels of activity and calculated their synthetic spectra. A comparison of these spectra revealed two spectral regions most significantly impacted by activity: approximately 3300–4400 Å and 5250–5500 Å. By calculating the total contribution function of the lines, we determined that the emergence of a secondary chromospheric contribution to line formation is the primary mechanism driving these changes. Based on our calculations and analysis, we compiled a list of transition lines and their corresponding changes due to chromospheric activity. This list could serve as a valuable tool for selecting spectral lines applicable to a wide range of astrophysical studies.https://doi.org/10.3847/1538-4357/adb0c6Stellar chromospheresStellar activityLate-type dwarf stars
spellingShingle Mariela C. Vieytes
Lily L. Zhao
Megan Bedell
The Influence of Chromospheric Activity on Line Formation
The Astrophysical Journal
Stellar chromospheres
Stellar activity
Late-type dwarf stars
title The Influence of Chromospheric Activity on Line Formation
title_full The Influence of Chromospheric Activity on Line Formation
title_fullStr The Influence of Chromospheric Activity on Line Formation
title_full_unstemmed The Influence of Chromospheric Activity on Line Formation
title_short The Influence of Chromospheric Activity on Line Formation
title_sort influence of chromospheric activity on line formation
topic Stellar chromospheres
Stellar activity
Late-type dwarf stars
url https://doi.org/10.3847/1538-4357/adb0c6
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