The Gaia-ESO Survey: Galactic evolution of sulphur and zinc^⋆,⋆⋆

¹ Millennium Institute of Astrophysics, 1515 Santiago, Chile
e-mail: sonia.duffau@gmail.com
² Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile
³ Departamento de Ciencias Fisicas, Universidad Andres Bello, Fernandez Concha 700, Las Condes, Santiago, Chile
⁴ GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, 92195 Meudon, France
⁵ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago de Chile, Chile
⁶ Department of Astronomy and Astronomical Observatory, Odessa National University, Isaac Newton Institute of Chile, Odessa Branch, Shevchenko Park, 65014 Odessa, Ukraine
⁷ Crimean Astrophysical Observatory, 298409 Nauchny, Crimea
⁸ UPJV, Université de Picardie Jules Verne, 33 rue St Leu, 80080 Amiens, France
⁹ Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
¹⁰ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹¹ INAF–Osservatorio Astronomico di Bologna, via Gobetti 93/3, 40129 Bologna, Italy
¹² Dipartimento di Astronomia, Universitá di Bologna, via Gobetti 93/2, 40129 Bologna, Italy
¹³ Universidade de Sao Paulo, IAG, Departamento de Astronomia, Rua do Matao 1226, 05509-900 Sao Paulo, SP, Brasil
¹⁴ Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, 69117 Heidelberg, Germany
¹⁵ Technische Universität Darmstadt, Schlossgartenstr. 2, 64289 Darmstadt, Germany
¹⁶ Dark Cosmology Centre, The Niels Bohr Institute, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
e-mail: cjhansen@dark-cosmology.dk
¹⁷ Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
¹⁸ Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5, 35122 Padova, Italy
¹⁹ Observatoire de Genève, Université de Genève, C 1290 Versoix, Switzerland
²⁰ Department of Astronomy, Indiana University, 727 East 3rd St, Swain West 318, Bloomington, IN 47405, USA
²¹ Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
²² Phyics Department,Lancaster University, Lancaster LA1 4YB, UK
²³ INAF–Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Florence, Italy
²⁴ ASI Science Data Center, Via del Politecnico SNC, 00133 Roma, Italy
²⁵ Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Chile
²⁶ Institute of Theoretical Physics and Astronomy, Vilnius University, Sauletekio av. 3, 10222 Vilnius, Lithuania
²⁷ Department of Astronomy, Columbia University, 550 W 120th St, New York, NY 10027, USA
²⁸ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
²⁹ Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, 221 00 Lund, Sweden
³⁰ Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland
³¹ Instituto de Física y Astronomía, Universidad de Valparaíso, 951 Valparaíso, Chile
³² Dipartimento di Fisica e Astronomia, Universitá di Padova, Vicolo Osservatorio 3, 35122 Padova, Italy
³³ Instituto de Astrofísica de Andalucía-CSIC, Apdo. 3004, 18080 Granada, Spain
³⁴ INAF–Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
³⁵ Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
³⁶ Laboratoire d’astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
³⁷ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal

Received: 20 January 2017
Accepted: 10 April 2017

Abstract

Context. Due to their volatile nature, when sulphur and zinc are observed in external galaxies, their determined abundances represent the gas-phase abundances in the interstellar medium. This implies that they can be used as tracers of the chemical enrichment of matter in the Universe at high redshift. Comparable observations in stars are more difficult and, until recently, plagued by small number statistics.

Aims. We wish to exploit the Gaia-ESO Survey (GES) data to study the behaviour of sulphur and zinc abundances of a large number of Galactic stars, in a homogeneous way.

Methods. By using the UVES spectra of the GES sample, we are able to assemble a sample of 1301 Galactic stars, including stars in open and globular clusters in which both sulphur and zinc were measured.

Results. We confirm the results from the literature that sulphur behaves as an α-element. We find a large scatter in [Zn/Fe] ratios among giant stars around solar metallicity. The lower ratios are observed in giant stars at Galactocentric distances less than 7.5 kpc. No such effect is observed among dwarf stars, since they do not extend to that radius.

Conclusions. Given the sample selection, giants and dwarfs are observed at different Galactic locations, and it is plausible, and compatible with simple calculations, that Zn-poor giants trace a younger population more polluted by SN Ia yields. It is necessary to extend observations in order to observe both giants and dwarfs at the same Galactic location. Further theoretical work on the evolution of zinc is also necessary.