posted on 2019-06-13, 08:34authored byG Collaboration, C Babusiaux, FV Leeuwen, MA Barstow, C Jordi, A Vallenari, D Bossini, A Bressan, T Cantat-Gaudin, MV Leeuwen, AGA Brown, T Prusti, JHJD Bruijne, CAL Bailer-Jones, M Biermann, DW Evans, L Eyer, F Jansen, SA Klioner, U Lammers, L Lindegren, X Luri, F Mignard, C Panem, D Pourbaix, S Randich, P Sartoretti, HI Siddiqui, C Soubiran, NA Walton, F Arenou, U Bastian, M Cropper, R Drimmel, D Katz, MG Lattanzi, J Bakker, C Cacciari, J Castañeda, L Chaoul, N Cheek, F DeAngeli, C Fabricius, R Guerra, B Holl, E Masana, R Messineo, N Mowlavi, K Nienartowicz, P Panuzzo, J Portell, M Riello, GM Seabroke, P Tanga, F Thévenin, G Gracia-Abril, G Comoretto, M Garcia-Reinaldos, D Teyssier, M Altmann, R Andrae, M Audard, I Bellas-Velidis, K Benson, J Berthier, R Blomme, P Burgess, G Busso, B Carry, A Cellino, G Clementini, M Clotet, O Creevey, M Davidson, J DeRidder, L Delchambre, A Dell'Oro, C Ducourant, J Fernández-Hernández, M Fouesneau, Y Frémat, L Galluccio, M García-Torres, J González-Núñez, JJ González-Vidal, E Gosset, LP Guy, J-L Halbwachs, NC Hambly, DL Harrison, J Hernández, D Hestroffer, ST Hodgkin, A Hutton, G Jasniewicz, A Jean-Antoine-Piccolo, S Jordan, AJ Korn, A Krone-Martins, AC Lanzafame, T Lebzelter, W Löffler, M Manteiga, PM Marrese, JM Martín-Fleitas, A Moitinho, A Mora, K Muinonen, J Osinde, E Pancino, T Pauwels, J-M Petit, A Recio-Blanco, PJ Richards, L Rimoldini, AC Robin, LM Sarro, C Siopis, M Smith, A Sozzetti, M Süveges, J Torra, W vanReeven, U Abbas, AA Aramburu, S Accart, C Aerts, G Altavilla, MA Álvarez, R Alvarez, J Alves, RI Anderson, AH Andrei, EA Varela, E Antiche, T Antoja, B Arcay, TL Astraatmadja, N Bach, SG Baker, L Balaguer-Núñez, P Balm, C Barache, C Barata, D Barbato, F Barblan, PS Barklem, D Barrado, M Barros, SB Muñoz, J-L Bassilana, U Becciani, M Bellazzini, A Berihuete, S Bertone, L Bianchi, O Bienaymé, S Blanco-Cuaresma, T Boch, C Boeche, A Bombrun, R Borrachero, S Bouquillon, G Bourda, A Bragaglia, L Bramante, MA Breddels, N Brouillet, T Brüsemeister, E Brugaletta, B Bucciarelli, A Burlacu, D Busonero, AG Butkevich, R Buzzi, E Caffau, R Cancelliere, G Cannizzaro, R Carballo, T Carlucci, JM Carrasco, L Casamiquela, M Castellani, A Castro-Ginard, P Charlot, L Chemin, A Chiavassa, G Cocozza, G Costigan, S Cowell, F Crifo, M Crosta, C Crowley, J Cuypers, C Dafonte, Y Damerdji, A Dapergolas, P David, M David, P deLaverny, F DeLuise, R DeMarch, D deMartino, R deSouza, A deTorres, J Debosscher, E delPozo, M Delbo, A Delgado, HE Delgado, S Diakite, C Diener, E Distefano, C Dolding, P Drazinos, J Durán, B Edvardsson, H Enke, K Eriksson, P Esquej, GE Bontemps, C Fabre, M Fabrizio, S Faigler, AJ Falcão, MF Casas, L Federici, G Fedorets, P Fernique, F Figueras, F Filippi, K Findeisen, A Fonti, E Fraile, M Fraser, B Frézouls, M Gai, S Galleti, D Garabato, F García-Sedano, A Garofalo, N Garralda, A Gavel, P Gavras, J Gerssen, R Geyer, P Giacobbe, G Gilmore, S Girona, G Giuffrida, F Glass, M Gomes, M Granvik, A Gueguen, A Guerrier, J Guiraud, R Gutiérrez-Sánchez, R Haigron, D Hatzidimitriou, M Hauser, M Haywood, U Heiter, A Helmi, J Heu, T Hilger, D Hobbs, W Hofmann, G Holland, HE Huckle, A Hypki, V Icardi, K Janßen, G JevardatdeFombelle, PG Jonker, ÁL Juhász, F Julbe, A Karampelas, A Kewley, J Klar, A Kochoska, R Kohley, K Kolenberg, M Kontizas, E Kontizas, SE Koposov, G Kordopatis, Z Kostrzewa-Rutkowska, P Koubsky, S Lambert, AF Lanza, Y Lasne, J-B Lavigne, Y LeFustec, C LePoncin-Lafitte, Y Lebreton, S Leccia, N Leclerc, I Lecoeur-Taibi, H Lenhardt, F Leroux, S Liao, E Licata, HEP Lindstrøm, TA Lister, E Livanou, A Lobel, M López, S Managau, RG Mann, G Mantelet, O Marchal, JM Marchant, M Marconi, S Marinoni, G Marschalkó, DJ Marshall, M Martino, G Marton, N Mary, D Massari, G Matijevič, T Mazeh, PJ McMillan, S Messina, D Michalik, NR Millar, D Molina, R Molinaro, L Molnár, P Montegriffo, R Mor, R Morbidelli, T Morel, D Morris, AF Mulone, T Muraveva, I Musella, G Nelemans, L Nicastro, L Noval, W O'Mullane, C Ordénovic, D Ordóñez-Blanco, P Osborne, C Pagani, I Pagano, F Pailler, H Palacin, L Palaversa, A Panahi, M Pawlak, AM Piersimoni, F-X Pineau, E Plachy, G Plum, E Poggio, E Poujoulet, A Prša, L Pulone, E Racero, S Ragaini, N Rambaux, M Ramos-Lerate, S Regibo, C Reylé, F Riclet, V Ripepi, A Riva, A Rivard, G Rixon, T Roegiers, M Roelens, M Romero-Gómez, N Rowell, F Royer, L Ruiz-Dern, G Sadowski, TS Sellés, J Sahlmann, J Salgado, E Salguero, N Sanna, T Santana-Ros, M Sarasso, H Savietto, M Schultheis, E Sciacca, M Segol, JC Segovia, D Ségransan, I-C Shih, L Siltala, AF Silva, RL Smart, KW Smith, E Solano, F Solitro, R Sordo, S SoriaNieto, J Souchay, A Spagna, F Spoto, U Stampa, IA Steele, H Steidelmüller, CA Stephenson, H Stoev, FF Suess, J Surdej, L Szabados, E Szegedi-Elek, D Tapiador, F Taris, G Tauran, MB Taylor, R Teixeira, D Terrett, P Teyssandier, W Thuillot, A Titarenko, F TorraClotet, C Turon, A Ulla, E Utrilla, S Uzzi, M Vaillant, G Valentini, V Valette, A vanElteren, EV Hemelryck, M Vaschetto, A Vecchiato, J Veljanoski, Y Viala, D Vicente, S Vogt, C vonEssen, H Voss, V Votruba, S Voutsinas, G Walmsley, M Weiler, O Wertz, T Wevers, Ł Wyrzykowski, A Yoldas, M Žerjal, H Ziaeepour, J Zorec, S Zschocke, S Zucker, C Zurbach, T Zwitter
We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples. We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects. The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics. Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies.
Funding
We thank Pierre Bergeron for providing the WD tracks
in the Gaia DR2 passbands. This work presents results from the European
Space Agency (ESA) space mission Gaia. Gaia data are being processed by
the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the
DPAC is provided by national institutions, in particular the institutions participating in the Gaia MultiLateral Agreement (MLA). The Gaia mission
website is https://www.cosmos.esa.int/gaia. The Gaia archive website is https://archives.esac.esa.int/gaia. The Gaia mission and
data processing have financially been supported by, in alphabetical order by
country: the Algerian Centre de Recherche en Astronomie, Astrophysique et
Géophysique of Bouzareah Observatory; the Austrian Fonds zur Förderung
der wissenschaftlichen Forschung (FWF) Hertha Firnberg Programme through
grants T359, P20046, and P23737; the BELgian federal Science Policy Office
(BELSPO) through various PROgramme de Développement d’Expériences scientifiques (PRODEX) grants and the Polish Academy of Sciences – Fonds
Wetenschappelijk Onderzoek through grant VS.091.16N; the Brazil-France
exchange programmes Fundação de Amparo à Pesquisa do Estado de São
Paulo (FAPESP) and Coordenação de Aperfeicoamento de Pessoal de Nível
Superior (CAPES) – Comité Français d’Evaluation de la Coopération Universitaire et Scientifique avec le Brésil (COFECUB); the Chilean Dirección de
Gestión de la Investigación (DGI) at the University of Antofagasta and the
Comité Mixto ESO-Chile; the National Science Foundation of China (NSFC)
through grants 11573054 and 11703065; the Czech-Republic Ministry of Education, Youth, and Sports through grant LG 15010, the Czech Space Office
through ESA PECS contract 98058, and Charles University Prague through grant PRIMUS/SCI/17; the Danish Ministry of Science; the Estonian Ministry of Education and Research through grant IUT40-1; the European Commission’s Sixth
Framework Programme through the European L
History
Citation
Astronomy and Astrophysics, 2018, 616, A10
Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
Version
VoR (Version of Record)
Published in
Astronomy and Astrophysics
Publisher
EDP Sciences for European Southern Observatory (ESO)
Published in the A&A Gaia Data Release 2 special issue. Tables 2 and A.4 corrected. Tables available at http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A10