Chemical compositions of Galactic bulge stars

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{deg},-7.5{deg}, and -5{deg}. 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]~<-0.8 is enhanced in the elements associated with core collapse supernovae (SNeII). 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.

Cone search capability for table J/MNRAS/486/5349/tableb1a (Abundances catalogue for 202 red giant branch and clump stars along the minor bulge axis at latitude b=-5{deg})

Cone search capability for table J/MNRAS/486/5349/tableb1b (Abundances catalogue for 315 red giant branch and clump stars along the minor bulge axis at latitude b=-7.5{deg})

Cone search capability for table J/MNRAS/486/5349/tableb1c (Abundances catalogue for 300 red giant branch and clump stars along the minor bulge axis at latitude b=-10{deg})

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/486/5349
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/486/5349
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/486/5349
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/486/5349
Provenance
Creator Duong L.; Asplund M.; Nataf D.M.; Freeman K.C.; Ness M.
Publisher CDS
Publication Year 2022
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Galactic and extragalactic Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics