The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge
Howes, Louise; Asplund, M.; Casey, A. R.; Keller, S. C., et al. (2014). The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge. Monthly Notices of the Royal Astronomical Society, 445, (4), 4241 - 4246
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Published
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English
Authors:
Howes, Louise
;
Asplund, M.
;
Casey, A. R.
;
Keller, S. C.
, et al.
Department:
Lund Observatory - Has been reorganised
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 [alpha/Fe] ratios.
Keywords:
stars: abundances ;
stars: Population II ;
Galaxy: bulge ;
Galaxy: ;
evolution
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