Gaia FGK benchmark stars: Selecting infrared lines for abundance determination
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.
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BibTeX
@article{elgueta2026gaia,
title = {{Gaia FGK benchmark stars: Selecting infrared lines for abundance determination}},
author = {S. Elgueta and P. Jofré and C. Aguilera-Gómez and D. Slumstrup and Á. Rojas Arriagada and U. Heiter and L. Casamiquela and M. Zoccali and C. Worley and C. Soubiran},
journal = {Astronomy \& Astrophysics - A\&A},
year = {2026},
month = jun,
doi = {10.1051/0004-6361/202659148},
eprint = {2602.14294},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05805548v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Gaia FGK benchmark stars: Selecting infrared lines for abundance determination
AU - S. Elgueta
AU - P. Jofré
AU - C. Aguilera-Gómez
AU - D. Slumstrup
AU - Á. Rojas Arriagada
AU - U. Heiter
AU - L. Casamiquela
AU - M. Zoccali
AU - C. Worley
AU - C. Soubiran
PY - 2026
DA - 2026/06/05
JO - Astronomy & Astrophysics - A&A
DO - 10.1051/0004-6361/202659148
UR - https://hal.science/hal-05805548v1
AB - 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.
SN - 0004-6361
SN - 1432-0746
ER -