The chemical DNA of the Magellanic Clouds -- I. The chemical composition of 206 Small Magellanic Cloud red giant stars

Abstract

We present the chemical composition of 206 red giant branch stars members of the Small Magellanic Cloud (SMC) using optical, high-resolution spectra collected with the multi-object spectrograph FLAMES-GIRAFFE at the ESO Very Large Telescope. This sample includes stars in three fields located in different positions within the parent galaxy. We analysed the main groups of elements, namely light- (Na), alpha- (O, Mg, Si, Ca, Ti), iron-peak (Sc, V, Fe, Ni, Cu) and s-process elements (Zr, Ba, La). The metallicity distribution of the sample displays a main peak around [Fe/H] ~ -1 dex and a weak metal-poor tail. However, the three fields display [Fe/H] distributions different with each other, in particular a difference of 0.2 dex is found between the mean metallicities of the two most internal fields.The fraction of metal-poor stars increases significantly (from ~1 to ~20%) from the innermost fields to the most external one, likely reflecting an age gradient in the SMC. Also, we found a hint of possible chemically/kinematic distinct substructures. The SMC stars have abundance ratios clearly distinct with respect to the Milky Way stars, in particular for the elements produced by massive stars (like Na, $\alpha$ and most iron-peak elements) that have abundance ratios systematically lower than those measured in our Galaxy. This points out that the massive stars contributed less to the chemical enrichment of the SMC with respect to the Milky Way, according to the low star formation rate expected for this galaxy. Finally, we identified small systematic differences in the abundances of some elements (Na, Ti, V and Zr) in the two innermost fields, suggesting that the chemical enrichment history in the SMC has been not uniform.

16 pages, 11 figures, 5 tables. Accepted for publication in Astronomy and Astrophysics

References in corpus (26)

• The Gaia mission
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• DAOSPEC: an automatic code for measuring equivalent widths in high-resolution stellar spectra
• The exotic chemical composition of the Sagittarius dwarf Spheroidal galaxy
• The influence of chemical composition on the properties of Cepheid stars. II-The iron content
• The evolution of CNO isotopes: a new window on cosmic star-formation history and the stellar IMF in the age of ALMA
• Clustering of Local Group distances: publication bias or correlated measurements? III. The Small Magellanic Cloud
• The Chemical Enrichment History of the Small Magellanic Cloud and Its Gradients
• The VMC Survey. XXV. The 3D structure of the Small Magellanic Cloud from Classical Cepheids
• Exploiting the Gaia EDR3 photometry to derive stellar temperatures
• Multiple populations in the old and massive Small Magellanic Cloud globular cluster NGC121
• The synchronised dance of the Magellanic Clouds' star formation history
• Red Giants in the Small Magellanic Cloud. II. Metallicity Gradient and Age-Metallicity Relation
• Nucleosynthesis imprints from different Type Ia Supernova explosion scenarios and implications for galactic chemical evolution
• Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. I. Constraints on the Star Formation History in Different Fields
• Contrasting copper evolution in Omega Centauri and the Milky Way
• Chemical Signature of a Major Merger in the Early Formation of Small Magellanic Cloud
• Non-LTE analysis of neutral copper in the late-type metal-poor stars
• Tagging the Chemical Evolution History of the Large Magellanic Cloud Disk
• Kinematical Structure of the Magellanic System
• The VMC survey -- XXXIX: Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands
• A homogeneous comparison between the chemical composition of the Large Magellanic Cloud and the Sagittarius dwarf galaxy
• The chemical composition of the stellar cluster Gaia1: no surprise behind Sirius
• Near-Infrared Photometry of Four Stellar Clusters in the Small Magellanic Cloud

Cited by in corpus (6)

• The R-Process Alliance: Fifth Data Release from the Search for R-Process-Enhanced Metal-poor Stars in the Galactic Halo with the GTC
• The GALAH survey: Tracing the Milky Way's formation and evolution through RR Lyrae stars
• The VISCACHA survey -- VIII. Chemical evolution history of Small Magellanic Cloud West Halo cluster
• Extragalactic 85Rb/87Rb and 6Li/7Li ratios in the Small Magellanic Cloud
• s-process Enriched Evolved Binaries in the Galaxy and the Magellanic Clouds
• Neutron-capture elements in a sample of field metal-poor N-rich dwarfs