| Issue |
A&A
Volume 666, October 2022
|
|
|---|---|---|
| Article Number | A125 | |
| Number of page(s) | 12 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361/202244013 | |
| Published online | 18 October 2022 | |
Abundances of disk and bulge giants from high-resolution optical spectra
V. Molybdenum: The p-process element★,★★
1
Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University,
Box 43,
22100
Lund, Sweden
e-mail: rebecca@astro.lu.se
2
Materials Science and Applied Mathematics, Malmö University,
205 06
Malmö, Sweden
3
Department of Physics and Astronomy, ICLA,
430 Portola Plaza,
Box 951547,
Los Angeles, CA
90095-1547, USA
4
Center for Star and Planet Formation, GLOBE Institute University of Copenhagen,
Øster Voldgade 5-7,
1350
Copenhagen, Denmark
Received:
10
May
2022
Accepted:
27
June
2022
Aims. In this work, we aim to make a differential comparison of the neutron-capture and p-process element molybdenum (Mo) in the stellar populations in the local disk(s) and the bulge, focusing on minimising possible systematic effects in the analysis.
Methods. The stellar sample consists of 45 bulge and 291 local disk K-giants observed with high-resolution optical spectra. The abundances are determined by fitting synthetic spectra using the Spectroscopy Made Easy (SME) code. The disk sample is separated into thin and thick disk components using a combination of abundances and kinematics. The cosmic origin of Mo is investigated and discussed by comparing with published abundances of Mo and the neutron-capture elements cerium (Ce) and europium (Eu).
Results. We determine reliable Mo abundances for 35 bulge and 282 disk giants with a typical uncertainty of [Mo/Fe] ~ 0.2 and ~0.1 dex for the bulge and disk, respectively.
Conclusions. We find that the bulge is possibly enhanced in [Mo/Fe] compared to the thick disk, which we do not observe in either [Ce/Fe] or [Eu/Fe]. This might suggest a higher past star-formation rate in the bulge; however, as we do not observe the bulge to be enhanced in [Eu/Fe], the origin of the molybdenum enhancement is yet to be constrained. Although the scatter is large, we may be observing evidence of the p-process contributing to the heavy element production in the chemical evolution of the bulge.
Key words: stars: abundances / Galaxy: abundances / Galaxy: bulge / Galaxy: disk / Galaxy: evolution / solar neighborhood
Full Tables A.1–A.4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/666/A125
Based on observations made with the Nordic Optical Telescope (programs 51-018 and 53-002) operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias, spectral data retrieved from PolarBase at Observatoire Midi Pyrénées, and observations collected at the European Southern Observatory, Chile (ESO programs 71.B-0617(A), 073.B-0074(A), and 085.B-0552(A)).
© R. Forsberg et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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