000006074 001__ 6074
000006074 005__ 20240108164652.0
000006074 0247_ $$2DOI$$a10.1051/0004-6361/202244156
000006074 037__ $$aSCART-2023-0035
000006074 100__ $$aLanzafame, A. C.
000006074 245__ $$aGaia Data Release 3. Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer 
000006074 260__ $$c2023
000006074 520__ $$aContext. The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta_lambda ~11500) 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 diagnostics 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. Scientific validation of the Gaia stellar activity index is performed by deriving a R_IRT index, 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 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 2x10^6 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 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 MS stars with Teff>= 5000K is also found, which defines the two other regimes, without a clear gap in between. Stars with 3500K>Teff>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 Teff>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.
000006074 536__ $$aGaia PRODEX/$$cGaia PRODEX/$$fGaia PRODEX
000006074 594__ $$aNO
000006074 6531_ $$aStars: activity
000006074 6531_ $$aStars: chromospheres
000006074 6531_ $$aStars: late-type
000006074 6531_ $$aStars: pre-main sequence
000006074 6531_ $$aMethods: data analysis
000006074 6531_ $$aCatalogs
000006074 700__ $$aBrugaletta, E.
000006074 700__ $$aFrémat, Y.
000006074 700__ $$aSordo, R.
000006074 700__ $$aCreevey, O. L.
000006074 700__ $$aAndretta, V.
000006074 700__ $$aScandariato, G.
000006074 700__ $$aBusà, I.
000006074 700__ $$aDistefano, E.
000006074 700__ $$aKorn, A. J.
000006074 700__ $$ade Laverny, P.
000006074 700__ $$aRecio-Blanco, A.
000006074 700__ $$aAbreu Aramburu, A.
000006074 700__ $$aÁlvarez, M. A.
000006074 700__ $$aAndrae, R.
000006074 700__ $$aBailer-Jones, C. A. L.
000006074 700__ $$aBakker, J.
000006074 700__ $$aBellas-Velidis, I.
000006074 700__ $$aBijaoui, A.
000006074 700__ $$aBrouillet, N.
000006074 700__ $$aBurlacu, A.
000006074 700__ $$aCarballo, R.
000006074 700__ $$aCasamiquela, L.
000006074 700__ $$aChaoul, L.
000006074 700__ $$aChiavassa, A.
000006074 700__ $$aContursi, G.
000006074 700__ $$aCooper, W. J.
000006074 700__ $$aDafonte, C.
000006074 700__ $$aDapergolas, A.
000006074 700__ $$aDelchambre, L.
000006074 700__ $$aDemouchy, C.
000006074 700__ $$aDharmawardena, T. E.
000006074 700__ $$aDrimmel, R.
000006074 700__ $$aEdvardsson, B.
000006074 700__ $$aFouesneau, M.
000006074 700__ $$aGarabato, D.
000006074 700__ $$aGarcía-Lario, P.
000006074 700__ $$aGarcía-Torres, M.
000006074 700__ $$aGavel, A.
000006074 700__ $$aGomez, A.
000006074 700__ $$aGonzález-Santamaría, I.
000006074 700__ $$aHatzidimitriou, D.
000006074 700__ $$aHeiter, U.
000006074 700__ $$aJean-Antoine Piccolo, A.
000006074 700__ $$aKontizas, M.
000006074 700__ $$aKordopatis, G.
000006074 700__ $$aLebreton, Y.
000006074 700__ $$aLicata, E. L.
000006074 700__ $$aLindstrøm, H. E. P.
000006074 700__ $$aLivanou, E.
000006074 700__ $$aLobel, A.
000006074 700__ $$aLorca, A.
000006074 700__ $$aMagdaleno Romeo, A.
000006074 700__ $$aManteiga, M.
000006074 700__ $$aMarocco, F.
000006074 700__ $$aMarshall, D. J.
000006074 700__ $$aMary, N.
000006074 700__ $$aNicolas, C.
000006074 700__ $$aOrdenovic, C.
000006074 700__ $$aPailler, F.
000006074 700__ $$aPalicio, P. A.
000006074 700__ $$aPallas-Quintela, L.
000006074 700__ $$aPanem, C.
000006074 700__ $$aPichon, B.
000006074 700__ $$aPoggio, E.
000006074 700__ $$aRiclet, F.
000006074 700__ $$aRobin, C.
000006074 700__ $$aRybizki, J.
000006074 700__ $$aSantoveña, R.
000006074 700__ $$aSarro, L. M.
000006074 700__ $$aSchultheis, M. S.
000006074 700__ $$aSegol, M.
000006074 700__ $$aSilvelo, A.
000006074 700__ $$aSlezak, I.
000006074 700__ $$aSmart, R. L.
000006074 700__ $$aSoubiran, C.
000006074 700__ $$aSüveges, M.
000006074 700__ $$aThévenin, F.
000006074 700__ $$aTorralba Elipe, G.
000006074 700__ $$aUlla, A.
000006074 700__ $$aUtrilla, E.
000006074 700__ $$aVallenari, A.
000006074 700__ $$avan Dillen, E.
000006074 700__ $$aZhao, H.
000006074 700__ $$aZorec, J.
000006074 773__ $$cA30 (18pp)$$pAstronomy & Astrophysics$$v674$$y2023
000006074 8560_ $$fronny.blomme@observatoire.be
000006074 85642 $$ahttps://ui.adsabs.harvard.edu/abs/2022arXiv220605766L/abstract
000006074 85642 $$ahttps://arxiv.org/abs/2206.05766
000006074 905__ $$apublished in
000006074 980__ $$aREFERD