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.
Zinc abundances in the Sculptor dwarf spheroidal galaxy / Skuladottir, A.; Tolstoy, E.; Salvadori, Stefania; Hill, V.; Pettini, M.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - STAMPA. - 606:(2017), pp. A71-A84. [10.1051/0004-6361/201731158]
Zinc abundances in the Sculptor dwarf spheroidal galaxy
Skuladottir, A.;SALVADORI, STEFANIA;
2017
Abstract
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.
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