Work

Hint of a bimodal Mg–Al anticorrelation in the metal-poor globular cluster NGC 4372

Year: 2026

Type: article

Abstract: We present a detailed chemical abundance analysis of seven red giant branch stars in the very metal-poor globular cluster NGC 4372 based on high-resolution UVES spectra. Our study aims to characterize the chemical evolution of NGC 4372 and investigate the presence of multiple populations. We derived abundances for 17 elements, including light, iron-peak, α , and heavy elements, using both equivalent width and spectral synthesis methods. We find a mean cluster metallicity of [Fe/H]=−2.36 ± 0.03 dex, with no evidence of an intrinsic iron spread. The cluster exhibits a typical α -enhancement of [ α /Fe]= 0.33 ± 0.05 dex and a well-defined Na-O anticorrelation, confirming that NGC 4372 hosts at least two distinct stellar populations. Furthermore, the measured ratio of [Ba/Eu]=−0.47 ± 0.04 indicates that the synthesis of heavy elements was dominated by the r -process, consistent with other very metal-poor environments. We also identify a potential bimodal Mg–Al anticorrelation, which aligns with the patterns observed in globular clusters of similar masses and metallicities. These results reinforce the status of NGC 4372 as a cornerstone for understanding the early chemical enrichment of the Galactic halo.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202661870

Authors: Camila Beltrand, Macarena Uribe, Sandro Villanova, Cesar Muñoz

Institutions: Universidad Central de Chile, University of La Serena, Universidad Andrés Bello

Language: English

Topic: Stellar, planetary, and galactic studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funder: Agencia Nacional de Investigación y Desarrollo