The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge

Louise M. Howes, Martin Asplund, A. R. Casey, S. C. Keller, David Yong, Gerry Gilmore, Karin Lind, Kim C Worley, Michael Stanley Bessell, Luca Casagrande, Anna F Marino, David M Nataf, C. I. Owen, Gary Stewart Da Costa, B. P. Schmidt, Patrick Tisserand, Sofia Randich, Sofia Feltzing, A. Vallenari, C. Allende PrietoM. Bergemann

Research output: Contribution to journalArticleResearchpeer-review

40 Citations (Scopus)

Abstract

We present the first results of the EMBLA survey (Extremely Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge, where the oldest stars should now preferentially reside. EMBLA utilizes SkyMapper photometry to pre-select metal-poor candidates, which are subsequently confirmed using AAOmega spectroscopy. We describe the discovery and analysis of four bulge giants with -2.72 = [Fe/H] = -2.48, the lowest metallicity bulge stars studied with high-resolution spectroscopy to date. Using FLAMES/UVES spectra through the Gaia-ESO Survey we have derived abundances of twelve elements. Given the uncertainties, we find a chemical similarity between these bulge stars and halo stars of the same metallicity, although the abundance scatter may be larger, with some of the stars showing unusual [a/Fe] ratios.

Original languageEnglish
Pages (from-to)4241-4246
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Volume445
Issue number4
DOIs
Publication statusPublished - 29 Sep 2014
Externally publishedYes

Keywords

  • Abundances-stars
  • Bulge-Galaxy
  • Evolution
  • Population II-Galaxy
  • Stars

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