English

Zinc in the Sculptor dwarf spheroidal galaxy

Astrophysics of Galaxies 2017-10-18 v1

Abstract

From ESO VLT/FLAMES/GIRAFFE spectra, abundance measurements of Zn have been made in \approx100 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]0.9-2.7\leq\text{[Fe/H]}\leq-0.9, the general trend of Zn abundances in Sculptor is similar to that of α\alpha-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\text{[Fe/H]}\gtrsim-1.8, we find a significant scatter, 0.8[Zn/Fe]+0.4-0.8\lesssim\text{[Zn/Fe]}\lesssim+0.4, which is not seen in any α\alpha-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\alpha- nor an iron-peak element.

Keywords

Cite

@article{arxiv.1708.00511,
  title  = {Zinc in the Sculptor dwarf spheroidal galaxy},
  author = {Ása Skúladóttir and Eline Tolstoy and Stefania Salvadori and Vanessa Hill and Max Pettini},
  journal= {arXiv preprint arXiv:1708.00511},
  year   = {2017}
}

Comments

Accepted in A&A, 14 pages, 16 figures, 8 tables