Abundances of disk and bulge giants from high-resolution optical spectra. V. Molybdenum: The p-process element
Abstract
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.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- October 2022
- DOI:
- 10.1051/0004-6361/202244013
- arXiv:
- arXiv:2206.13575
- Bibcode:
- 2022A&A...666A.125F
- Keywords:
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- stars: abundances;
- Galaxy: abundances;
- Galaxy: bulge;
- Galaxy: disk;
- Galaxy: evolution;
- solar neighborhood;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in A&