Gaia Data Release 2. Observational Hertzsprung-Russell diagrams
- Autor(en)
- , C. Babusiaux, F. van Leeuwen, M. A. Barstow, C. Jordi, A. Vallenari, D. Bossini, A. Bressan, T. Cantat-Gaudin, M. van Leeuwen, A. G. A. Brown, T. Prusti, J. H. J. de Bruijne, C. A. L. Bailer-Jones, M. Biermann, D. W. Evans, L. Eyer, F. Jansen, S. A. Klioner, U. Lammers, L. Lindegren, X. Luri, F. Mignard, C. Panem, D. Pourbaix, S. Randich, P. Sartoretti, H. I. Siddiqui, C. Soubiran, N. A. Walton, F. Arenou, U. Bastian, M. Cropper, R. Drimmel, D. Katz, M. G. Lattanzi, J. Bakker, C. Cacciari, J. Castañeda, L. Chaoul, N. Cheek, F. De Angeli, C. Fabricius, R. Guerra, B. Holl, E. Masana, R. Messineo, N. Mowlavi, K. Nienartowicz, T. Lebzelter, J. Alves
- Abstrakt
Context. Gaia Data Release 2 provides high-precision astrometry and three-band photometry for about 1.3 billion sources over the full sky. The precision, accuracy, and homogeneity of both astrometry and photometry are unprecedented.
Aims. 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.
Methods. 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.
Results. 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.
Conclusions. 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.- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Centre National De La Recherche Scientifique (CNRS), Université Paris VII - Paris-Diderot, University of Cambridge, University of Leicester, Universitat de Barcelona, INAF - Osservatorio Astronomico di Padova, Scuola Internazionale Superiore di Studi Avanzati, Leiden University, European Space Research & Technology Centre (ESA/ESTEC), Max-Planck-Institut für Astronomie, Universität Heidelberg, Universität Genf, Technische Universität Dresden, European Space Astronomy Centre (ESA), Lund Observatory, Université Côte d'Azur, Centre national d'études spatiales (CNES), Université Libre de Bruxelles, Fonds de la Recherche Scientifique, INAF - Osservatorio Astrofisico di Arcetri, Universität Bordeaux, University College London, INAF-Osservatorio Astrofisico di Torino, INAF-Osservatorio Astronomico di Bologna, ALTEC – Aerospace Logistics Technology Engineering Company
- Journal
- Astronomy & Astrophysics
- Band
- 616
- Anzahl der Seiten
- 29
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361/201832843
- Publikationsdatum
- 08-2018
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103003 Astronomie, 103004 Astrophysik
- Schlagwörter
- ASJC Scopus Sachgebiete
- Astronomy and Astrophysics, Space and Planetary Science
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/ad362a5f-8aac-40ba-b8a4-dedc05aeb252