2018/06/08 by L. Monaco, S. Villanova, G. Carraro +2 · 17 citations
Physics and Astronomy · #Abundance (ecology) #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Context (archaeology) #Geology #Giant star #Globular cluster #Horizontal branch #Metallicity #Physics #Population #Red giant #Red-giant branch #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201832979
published in Astronomy and Astrophysics 616, A181 (EDP Sciences) · 9 pages, 7 figures, 3 tables, accepted for publication in A&A
arxiv created 2018/06/08 · openalex publication_date 2018/06/09 · arxiv updated 2018/09/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Context . Globular clusters are known to host multiple stellar populations, which are a signature of their formation process. The globular cluster E3 is one of the few low-mass globulars that is thought not to host multiple populations. Aims . We investigate red giant branch stars in E3 with the aim of providing a first detailed chemical inventory for this cluster, we determine its radial velocity, and we provide additional insights into the possible presence of multiple populations in this cluster. Methods . We obtained high-resolution FLAMES-UVES/VLT spectra of four red giant branch stars likely members of E3. We performed a local thermodynamic equilibrium abundance analysis based on one-dimensional plane parallel ATLAS9 model atmospheres. Abundances were derived from line equivalent widths or spectrum synthesis. Results . We measured abundances of Na and of iron peak (Fe, V, Cr, Ni, Mn), α (Mg, Si, Ca, Ti), and neutron capture elements (Y, Ba, Eu). The mean cluster heliocentric radial velocity, metallicity, and sodium abundance ratio are ν helio = 12.6 ± 0.4 km s −1 ( σ = 0.6 ± 0.2 km s −1 ), [Fe/H] = −0.89 ± 0.08 dex, and [Na/Fe] = 0.18 ± 0.07 dex, respectively. The low Na abundance with no appreciable spread is suggestive of a cluster dominated by first-generation stars in agreement with results based on lower resolution spectroscopy. The low number of stars observed does not allow us to rule out a minor population of second-generation stars. The observed chemical abundances are compatible with the trends observed in Milky Way stars.