Gaia FGK benchmark stars: Selecting infrared lines for abundance determination
Year: 2026
Type: article
Abstract: The advent of new and more powerful infrared spectrographs has significantly motivated the advancement of the study of atomic and molecular line lists and stellar atmosphere models. While optical abundance determinations rely on extensively validated line lists and modeling frameworks, infrared measurements still face comparatively larger uncertainties, largely driven by the choice of atmospheric models and the quality of the available atomic data. In this work, we aim to deliver a homogeneous and reproducible set of atomic absorption lines in the Y, J , and H bands (9800–18 000 Å) based exclusively on laboratory atomic data. We analyzed CRIRES spectra of six Gaia FGK benchmark stars spanning a wide range in effective temperature, surface gravity, and chemical composition. Synthetic spectra were computed using the benchmark stellar parameters, and each transition was evaluated independently in every star through a quantitative sequence that examines line depth, saturation, blending (purity), and the agreement between observed and synthetic line profiles. We identified a set of robust atomic transitions in these bands that remain consistent across the full range of stellar parameters represented in our sample. Lines of α -elements such as Mg I , Si I , and Ca I , together with several Fe I transitions, satisfy all robustness criteria. Among the neutron-capture species explored, only Sr II provides lines that consistently meet our requirements. Beyond the specific list of accepted transitions, this study demonstrates that a fully quantitative multi-criteria framework provides a transparent and reproducible foundation for near-infrared line validation as laboratory data, stellar atmosphere models, and instrumentation continue to improve.
Source: Astronomy and Astrophysics
Institutions: Universidad de Santiago de Chile, Universidad Andrés Bello, Universidad Diego Portales, Pontificia Universidad Católica de Chile, Instituto de Astrofísica de Canarias, Uppsala University, Centre National de la Recherche Scientifique, Université Paris Cité, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, CY Cergy Paris Université, University of Canterbury, Laboratoire d'Astrophysique de Bordeaux
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7156212541