RSAA Colloquia / Seminars / Feast-of-Facts: Tuesday, 09 February 2016, 11:00-12:00; Duffield Lecture Theatre

Andreas Koch

"Bulge vs. Halo: a mixed bag of chemical enrichments"

The bulge is one of the oldest, yet very metal-rich Galactic components suggesting that it experienced early, rapid chemical enrichment. Yet, the first, metal-poor stars to have formed in the Universe are predicted to be found in this central region of the Milky Way. I will present results from our endeavour to detect and characterize signatures from such stars. The chemical abundances of our candidates (at [Fe/H] of -1.5 to -2.6 dex) vastly overlap with those of halo stars and our sample also contains one CEMP-s and a CH-star - the first detections of such objects in the bulge. While we do not see any evidence of Population III enrichment in our sample, the chemical abundance patterns still give a deep insight into the dominant enrichment mechanisms in the early phases of galaxy assembly. This can be contrasted to observations of other, most metal-poor stellar systems such as globular clusters.