Chemical Evolution of Yb in Galactic Disc

DOI

Measuring the abundances of neutron-capture elements in Galactic disk stars is an important part of understanding key stellar and galactic processes. In the optical wavelength regime a number of different neutron-capture elements have been measured; however, only the s-process-dominated element cerium has been accurately measured for a large sample of disk stars from the infrared H band. The more r-process dominated element ytterbium has only been measured in a small subset of stars so far. In this study we aim to measure the ytterbium (Yb) abundance of local disk giants using the Yb II line at {lambda}air=16498{AA}. We also compare the resulting abundance trend with cerium and europium abundances for the same stars to analyse the s- and r-process contributions. We analyse 30K giants with high-resolution H band spectra using spectral synthesis. The very same stars have already been analysed using high-resolution optical spectra via the same method, but it was not possible to determine the abundance of Yb from those spectra due to blending issues for stars with [Fe/H]>-1. In the present analysis, we utilise the stellar parameters determined from the optical analysis. We determined the Yb abundances with an estimated uncertainty for [Yb/Fe] of 0.1dex. By comparison, we found that the [Yb/Fe] trend closely follows the [Eu/Fe] trend and has clear s-process enrichment in identified s-rich stars. This comparison confirms both that the validity of the Yb abundances is ensured and that the theoretical prediction that the s-/r-process contribution to the origin of Yb of roughly 40/60 is supported. These results show that, with a careful and detailed analysis of infrared spectra, reliable Yb abundances can be derived for a wider sample of cooler giants in the range -1.1<[Fe/H]<0.3. This is promising for further studies of the production of Yb and for the r-process channel, key for galactochemical evolution, in the infrared.

Cone search capability for table J/A+A/665/A135/table1 (Observational data for sample)

Identifier
DOI http://doi.org/10.26093/cds/vizier.36650135
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/A+A/665/A135
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/665/A135
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/665/A135
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/A+A/665/A135
Provenance
Creator Montelius M.; Forsberg R.; Ryde N.; Joensson H.; Afsar M.; Johansen A.,Kaplan K.F.; Kim H.; Mace G.; Sneden C.; Thorsbro B.
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; Stellar Astronomy