بيانات النشر: Uppsala universitet, Observationell astrofysik
Uppsala universitet, Teoretisk astrofysik
INAF Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.;Univ Catania, Dipartimento Fis & Astron Ettore Majorana, Via S Sofia 64, I-95123 Catania, Italy.
INAF Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
Univ Cote Dazur, CNRS, Lab Lagrange, Observ Cote Dazur, Bd Observ,CS 34229, F-06304 Nice 4, France.
INAF Osservatorio Astron Capodimonte, Salita Moiariello 16, I-80131 Naples, Italy.
ATG Europe European Space Agcy ESA, Camino Bajo Del Castillo S-N, Madrid 28692, Spain.
Univ A Coruna, Dept Comp Sci & Informat Technol, CIGUS CITIC, Campus Elvina S-N, La Coruna 15071, Spain.
Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
European Space Agcy ESA, European Space Astron Ctr ESAC, Camino Bajo Del Castillo S-N, Madrid 28692, Spain.
Natl Observ Athens, Athens 15236, Greece.
Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
Telespazio CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
Univ Cantabria, Dpto Matemat Aplicada & Ciencias Computac, ETS Ingenieros Caminos Canales & Puertos, Avda Castros S-N, Santander 39005, Spain.
Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.;Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
Univ Hertfordshire, Ctr Astrophys Res, Coll Lane, Hatfield AL10 9AB, Herts, England.;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, TO, Italy.
Univ Liege, Inst Astrophys & Geophys, 19C Allee 6 Aout, B-4000 Liege, Belgium.
Apave Sudeurope SAS CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, TO, Italy.
Pablo de Olavide Univ, Data Sci & Big Data Lab, Seville 41013, Spain.
Natl Observ Athens, Athens 15236, Greece.;Natl & Kapodistrian Univ Athens, Dept Astrophys Astron & Mech, Athens 15783, Greece.
Natl & Kapodistrian Univ Athens, Dept Astrophys Astron & Mech, Athens 15783, Greece.
Univ Paris, Univ PSL, Sorbonne Univ, CNRS,LESIA,Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.;Univ Rennes, CNRS, IPR Inst Phys Rennes, UMR 6251, F-35000 Rennes, France.
INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, TO, Italy.;Univ Copenhagen, Niels Bohr Inst, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark.;DXC Technol, Retortvej 8, DK-2500 Valby, Denmark.
Aurora Technol European Space Agcy ESA, Camino Bajo Del Castillo S-N, Madrid 28692, Spain.
Univ A Coruna, Dept Naut Sci & Marine Engn, CIGUS CITIC, Paseo Ronda 51, La Coruna 15071, Spain.
CALTECH, IPAC, Mail Code 100-22,1200 Calif E Blvd, Pasadena, CA 91125 USA.
Univ Toulouse, CNRS, UPS, CNES,IRAP, 9 Ave Colonel Roche,BP 44346, F-31028 Toulouse 4, France.
CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
Univ Cote Dazur, CNRS, Lab Lagrange, Observ Cote Dazur, Bd Observ,CS 34229, F-06304 Nice 4, France.;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, TO, Italy.
UNED, Dept Inteligencia Artificial, C Juan Del Rosal 16, Madrid 28040, Spain.
Univ Geneva, Inst Global Hlth, Geneva, Switzerland.
Univ Vigo, Dept Appl Phys, Vigo 36310, Spain.
Sorbonne Univ, Inst Astrophys Paris, CNRS, UMR7095, 98 Bis Bd Arago, F-75014 Paris, France.
نبذة مختصرة : Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 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 R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(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 a ffected 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 x 10(6) 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 R-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 T-eff >= 5000K is also found, which defines the two other regimes, without a clear ...
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