Zinc abundances in the Sculptor dwarf spheroidal galaxy

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. 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 http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A7