Gaia Data Release 3: Stellar chromospheric activity and mass accretion from Ca ii IRT observed by the Radial Velocity Spectrometer

Lanzafame, A. C., Brugaletta, E., Frémat, Y., Sordo, R., Creevey, O. L., Sarro Baro, Luis Manuel y et al. . (2022) Gaia Data Release 3: Stellar chromospheric activity and mass accretion from Ca ii IRT observed by the Radial Velocity Spectrometer. Astronomy & Astrophysics (A&A), 674, A30 (2023)

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Título Gaia Data Release 3: Stellar chromospheric activity and mass accretion from Ca ii IRT observed by the Radial Velocity Spectrometer
Autor(es) Lanzafame, A. C.
Brugaletta, E.
Frémat, Y.
Sordo, R.
Creevey, O. L.
Sarro Baro, Luis Manuel
et al.
Materia(s) Ingeniería Informática
Abstract The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (= 11 500) in the near-infrared (845􀀀872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late–type stars. Aims. Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods. The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R0 IRT index, which is largely independent of the photospheric parameters, and considering the correlation with the R0 HK index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be aected by mass accretion. The position of these stars in the colour–magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results. Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 106 stars in the Galaxy. This represents a ‘gold mine’ for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R0 HK datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with Te & 5000K is also found, which defines the two other regimes, without a clear gap in between. Stars with 3500K. Te . 5000K are found to be either very active PMS stars or active MS stars with a unimodal distribution in chromospheric activity. A dramatic change in the activity distribution is found for Te . 3500 K, with a dominance of low activity stars close to the transition between partially- and fully convective stars and a rise in activity down into the fully convective regime.
Palabras clave stars: activity
stars: chromospheres
stars: late-type
stars: pre-main sequence
methods: data analysis
catalogs
Editor(es) EDP Sciences
Fecha 2022
Formato application/pdf
Identificador bibliuned:95-Lmsarro-0017
http://e-spacio.uned.es/fez/view/bibliuned:95-Lmsarro-0017
DOI - identifier https://doi.org/10.1051/0004-6361/202244156
ISSN - identifier 0004-6361 ; e-ISSN: 1432-0746
Nombre de la revista Astronomy & Astrophysics (A&A)
Número de Volumen 674
Número de Issue 30
Publicado en la Revista Astronomy & Astrophysics (A&A), 674, A30 (2023)
Idioma eng
Versión de la publicación acceptedVersion
Tipo de recurso Article
Derechos de acceso y licencia http://creativecommons.org/licenses/by/4.0
info:eu-repo/semantics/openAccess
Tipo de acceso Acceso abierto
Notas adicionales La versión registrada de este artículo, publicado por primera vez en Astronomy & Astrophysics (2023) Vol. 674, A30, está disponible en línea en el sitio web del editor: EDP Sciences, https://doi.org/10.1051/0004-6361/202244156
Notas adicionales The registered version of this paper, first published in Astronomy & Astrophysics (2023) Vol.674, A30, is available online at the publisher's website: EDP Sciences, https://doi.org/10.1051/0004-6361/202244156

 
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Creado: Tue, 09 Apr 2024, 20:22:09 CET