Abundance of barium in the atmospheres of red giants in the Galactic globular cluster NGC 104 (47 Tuc)
arXiv:2109.05586 · doi:10.1051/0004-6361/202142056
Abstract
Context. While most (if not all) Type I Galactic globular clusters (GGCs) are characterised by spreads in the abundances of light chemical elements (e.g. Li, N, O, Na, Mg, Al), it is not yet well established whether similar spreads may exist in s-process elements as well. Aims. We investigated the possible difference in Ba abundance between the primordial (1P) and polluted (2P) stars in the Galactic globular cluster (GGC) 47 Tuc (NGC 104). For this, we obtained homogeneous abundances of Fe, Na, and Ba in a sample of 261 red giant branch (RGB) stars which is the largest sample used for Na and Ba abundance analysis in any GGC so far. Methods. Abundances of Na and Ba were determined using archival GIRAFFE/VLT spectra and 1D non-local thermodynamic equilibrium (NLTE) abundance analysis methodology. Results. Contrary to the finding of Gratton et al. (2013), we did not detect any significant Ba-Na correlation or 2P-1P Ba abundance difference in the sample of 261 RGB stars in 47 Tuc. This corroborates the result of D'Orazi et al. (2010) who found no statistically significant Ba-Na correlation in 110 RGB stars in this GGC. The average barium-to-iron ratio obtained in the sample of 261 RGB stars, , agrees well with those determined in Galactic field stars at this metallicity and may therefore represent the abundance of primordial proto-cluster gas that has not been altered during the subsequent chemical evolution of the cluster.
12 pages, 12 figures, 8 tables. Accepted for publication in A&A
References in corpus (18)
- A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
- What is a globular cluster? An observational perspective
- Determining stellar macroturbulence using asteroseismic rotational velocities from Kepler
- The elemental composition of the Sun I. The intermediate mass elements Na to Ca
- The elemental composition of the Sun III. The heavy elements Cu to Th
- Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites
- High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
- The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps
- Evolution of the Barium abundance in the early Galaxy from a NLTE analysis of the Ba lines in a homogeneous sample of EMP stars
- Carbon and Strontium Abundances of Metal-Poor Stars
- Observational constraints on the origin of the elements II. 3D non-LTE formation of Ba ii lines in the solar atmosphere
- Variations in the lithium abundances of turn off stars in the globular cluster 47 Tuc
- The chemical composition of red giants in 47 Tucanae I: Fundamental parameters and chemical abundance patterns
- Galactic globular cluster 47 Tucanae: new ties between the chemical and dynamical evolution of globular clusters?
- Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. IV. Oxygen diagnostics in extremely metal-poor red giants with infrared OH lines
- The Chemical Composition of Globular Clusters of Different Nature in our Galaxy
- Abundances in a sample of turnoff and subgiant stars in NGC 6121 (M4)
- Medium-resolution s-process Element Survey of 47 Tuc giant stars