Journal article
HERBS II: Detailed chemical compositions of Galactic bulge stars
Monthly notices of the Royal Astronomical Society, Vol.486(4), pp.5349-5361
07/01/2019
DOI: 10.1093/mnras/stz1183
Abstract
This work explores the detailed chemistry of the Milky Way bulge using the HERMES spectrograph on the Anglo-Australian Telescope. Here, we present the abundance ratios of 13 elements for 832 red giant branch and clump stars along the minor bulge axis at latitudes b = -10 degrees, -7.5 degrees, and -5 degrees. Our results show that none of the abundance ratios vary significantly with latitude. We also observe disc-like [Na/Fe] abundance ratios, which indicate that the bulge does not contain helium-enhanced populations as observed in some globular clusters. Helium enhancement is therefore not the likely explanation for the double red-clump observed in the bulge. We confirm that bulge stars mostly follow abundance trends observed in the disc. However, this similarity is not confirmed across all elements and metallicity regimes. The more metal-poor bulge population at [Fe/H] less than or similar to -0.8 is enhanced in the elements associated with core collapse supernovae (SNe1.1), In addition, the [La/Eu] abundance ratio suggests higher r-process contribution, and likely higher star formation in the bulge compared to the disc. This highlights the complex evolution in the bulge, which should be investigated further, both in terms of modelling; and with additional observations of the inner Galaxy.
Details
- Title: Subtitle
- HERBS II: Detailed chemical compositions of Galactic bulge stars
- Creators
- L. Duong - Australian National UniversityM. Asplund - Australian National UniversityD. M. Nataf - Johns Hopkins UniversityK. C. Freeman - Australian National UniversityM. Ness - Columbia University
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.486(4), pp.5349-5361
- Publisher
- Oxford Univ Press
- DOI
- 10.1093/mnras/stz1183
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Number of pages
- 13
- Grant note
- Allan C. and Dorothy H. Davis Fellowship CE170100013 / Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D); Australian Research Council National Science Foundation; National Science Foundation (NSF) FL110100012; DP160103747 / Australian Research Council National Aeronautics and Space Administration; National Aeronautics & Space Administration (NASA) A/2013B/13; A/2014A/25; A/2015A/19; A/2017A/18 / Australian Astronomical Observatory Zonta International District
- Language
- English
- Date published
- 07/01/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701829602771
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