Heavy elements Ba, La, Ce, Nd, and Eu in 56 Galactic bulge red giants
M Van der Swaelmen, B Barbuy, V Hill… - Astronomy & …, 2016 - aanda.org
Astronomy & Astrophysics, 2016•aanda.org
Aims. The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd,
and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from-
1.3 dex to 0.5 dex. Methods. We obtained high-resolution spectra of our giant stars using the
FLAMES-UVES spectrograph on the Very Large Telescope. We inspected four bulge fields
along the minor axis. Results. We measure the chemical evolution of heavy elements, as a
function of metallicity, in the Galactic bulge. Conclusions. The [Ba, La, Ce, Nd/Fe] vs.[Fe/H] …
and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from-
1.3 dex to 0.5 dex. Methods. We obtained high-resolution spectra of our giant stars using the
FLAMES-UVES spectrograph on the Very Large Telescope. We inspected four bulge fields
along the minor axis. Results. We measure the chemical evolution of heavy elements, as a
function of metallicity, in the Galactic bulge. Conclusions. The [Ba, La, Ce, Nd/Fe] vs.[Fe/H] …
Aims
The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd, and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from -1.3 dex to 0.5 dex.
Methods
We obtained high-resolution spectra of our giant stars using the FLAMES-UVES spectrograph on the Very Large Telescope. We inspected four bulge fields along the minor axis.
Results
We measure the chemical evolution of heavy elements, as a function of metallicity, in the Galactic bulge.
Conclusions
The [Ba,La,Ce,Nd/Fe] vs. [Fe/H] ratios decrease with increasing metallicity, in which aspect they differ from disc stars. In our metal-poor bulge stars, La and Ba are enhanced relative to their thick disc counterpart, while in our metal-rich bulge stars La and Ba are underabundant relative to their disc counterpart. Therefore, this contrast between bulge and discs trends indicates that bulge and (solar neighbourhood) thick disc stars could behave differently. An increase in [La,Nd/Eu] with increasing metallicity, for metal-rich stars with [Fe/H] > 0 dex, may indicate that the s-process from AGB stars starts to operate at a metallicity around solar. Finally, [Eu/Fe] follows the [α/ Fe] behaviour, as expected, since these elements are produced by SNe type II.
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