1 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
2 Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
3 Dipartimento di Fisica e Astronomia, Universita’ di Firenze, via G. Sansone 1, Sesto Fiorentino, Italy
4 INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, Firenze, Italy
5 GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jule Janssen, 92190 Meudon, France
6 Laboratoire Lagrange, Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, CS34229, 06304 Nice Cedex 4, France
7 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
Received: 11 May 2017
Accepted: 18 July 2017
From ESO VLT/FLAMES/GIRAFFE spectra, abundance measurements of Zn have been made in ≈100 individual red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy. This is the largest sample of individual Zn abundance measurements within a stellar system beyond the Milky Way. In the observed metallicity range, −2.7 ≤ [Fe/H] ≤ −0.9, the general trend of Zn abundances in Sculptor is similar to that of α-elements. That is, super-solar abundance ratios of [Zn/Fe] at low metallicities, which decrease with increasing [Fe/H], eventually reaching subsolar values. However, at the higher metallicities in Sculptor, [Fe/H] ≳ −1.8, we find a significant scatter, −0.8 ≲ [Zn/Fe] ≲ +0.4, which is not seen in any α-element. Our results are consistent with previous observations of a limited number of stars in Sculptor and in other dwarf galaxies. These results suggest that zinc has a complex nucleosynthetic origin, behaving neither completely like an α- nor an iron-peak element.
Key words: stars: abundances / galaxies: abundances / galaxies: dwarf / galaxies: evolution / Local Group
Based on observations made with ESO/VLT/FLAMES at the La Silla Paranal observatory under program ID 092.B-0194(A).
Tables 2–4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A71
© ESO, 2017