Issue |
A&A
Volume 612, April 2018
|
|
---|---|---|
Article Number | A99 | |
Number of page(s) | 30 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/201731738 | |
Published online | 04 May 2018 |
The Gaia-ESO Survey: open clusters in Gaia-DR1
A way forward to stellar age calibration★,★★
1
INAF–Osservatorio Astrofisico di Arcetri,
Largo E. Fermi 5,
50125 Firenze,
Italy
e-mail: randich@arcetri.astro.it
2
Department of Physics “E. Fermi”, University of Pisa,
Largo Bruno Pontecorvo 3,
56127 Pisa,
Italy
3
INFN,
Section of Pisa,
Largo Bruno Pontecorvo 3,
56127 Pisa,
Italy
4
Astrophysics Group, University of Keele,
Keele,
Staffordshire ST5 5BG,
UK
5
INAF–Osservatorio Astrofisico di Torino,
via Osservatorio 20,
10025 Pino Torinese,
Italy
6
INAF–Osservatorio Astronomico di Bologna,
via Gobetti 93/3,
40129 Bologna,
Italy
7
Instituto de Astrofìsica de Andalucìa (IAA-CSIC),
Glorieta de la Astronomìa,
18008 Granada,
Spain
8
Laboratoire d’Astrophysique de Bordeaux, Université Bordeaux, CNRS,
B18N, Allée Geoffroy Saint-Hilaire,
33615 Pessac,
France
9
Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze,
via G. Sansone 1,
50019 Sesto Fiorentino (Firenze),
Italy
10
Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica,
PO Box 78,
28691 Villanueva de la Cañada, Madrid,
Spain
11
Departament de Fìsìca Quantìca i Astrofìsica, Institut Cìencies Cosmos (ICCUB), Universitat de Barcelona,
08007 Barcelona,
Spain
12
Leiden Observatory,
Niels Bohrweg 2,
2333 CA Leiden,
The Netherlands
13
Institute of Theoretical Physics and Astronomy, Vilnius University,
Saulėtekio al. 3,
10222 Vilnius,
Lithuania
14
Institute of Astronomy, Madingley Road, University of Cambridge,
CB3 0HA,
UK
15
Lund Observatory, Department of Astronomy and Theoretical Physics,
Box 43, 221 00, Lund
Sweden
16
INAF–Osservatorio Astronomico di Padova,
Vicolo dell’Osservatorio 5,
35122 Padova,
Italy
17
Department of Physics and Astronomy, Uppsala University,
Box 516, 751 20 city,
Sweden
18
Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Università di Catania,
via S. Sofia 78,
95123 Catania,
Italy
19
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences,
ul. Bartycka 18,
00-716 Warsaw,
Poland
20
Instituto de Física y Astronomiía, Universidad de Valparíso,
Chile
21
Dipartimento di Fisica e Astronomia, Università di Padova, Vicolo dell’Osservatorio 3,
35122 Padova,
Italy
22
Núcleo de Astronomá, Universidad Diego Portales,
Av. Ejéxrcito 441,
Santiago,
Chile
23
Departamento de Ciencias Fisicas, Universidad Andres Bello,
Fernandez Concha 700,
Las Condes, Santiago,
Chile
24
INAF–Osservatorio Astronomico di Palermo,
Piazza del Parlamento 1,
90134 Palermo,
Italy
25
European Southern Observatory, Alonso de Cordova,
3107 Vitacura,
Santiago de Chile,
Chile
26
Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP,
Rua das Estrelas,
4150-762 Porto,
Portugal
Received:
8
August
2017
Accepted:
4
November
2017
Context. Determination and calibration of the ages of stars, which heavily rely on stellar evolutionary models, are very challenging, while representing a crucial aspect in many astrophysical areas.
Aims. We describe the methodologies that, taking advantage of Gaia-DR1 and the Gaia-ESO Survey data, enable the comparison of observed open star cluster sequences with stellar evolutionary models. The final, long-term goal is the exploitation of open clusters as age calibrators.
Methods. We perform a homogeneous analysis of eight open clusters using the Gaia-DR1 TGAS catalogue for bright members and information from the Gaia-ESO Survey for fainter stars. Cluster membership probabilities for the Gaia-ESO Survey targets are derived based on several spectroscopic tracers. The Gaia-ESO Survey also provides the cluster chemical composition. We obtain cluster parallaxes using two methods. The first one relies on the astrometric selection of a sample of bona fide members, while the other one fits the parallax distribution of a larger sample of TGAS sources. Ages and reddening values are recovered through a Bayesian analysis using the 2MASS magnitudes and three sets of standard models. Lithium depletion boundary (LDB) ages are also determined using literature observations and the same models employed for the Bayesian analysis.
Results. For all but one cluster, parallaxes derived by us agree with those presented in Gaia Collaboration (2017, A&A, 601, A19), while a discrepancy is found for NGC 2516; we provide evidence supporting our own determination. Inferred cluster ages are robust against models and are generally consistent with literature values.
Conclusions. The systematic parallax errors inherent in the Gaia DR1 data presently limit the precision of our results. Nevertheless, we have been able to place these eight clusters onto the same age scale for the first time, with good agreement between isochronal and LDB ages where there is overlap. Our approach appears promising and demonstrates the potential of combining Gaia and ground-based spectroscopic datasets.
Key words: parallaxes – surveys – stars: evolution – open clusters and associations: general
Based on observations collected with the FLAMES instrument at VLT/UT2 telescope (Paranal Observatory, ESO, Chile), for the Gaia-ESO Large Public Spectroscopic Survey (188.B-3002, 193.B-0936).
Additional tables are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A99
© ESO 2018
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.