Gaia FGK Benchmark Stars: Impact of Spectral Resolution on Stellar Abundances

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Main Authors: Hernández-Araya, Ivanna, Aguilera-Gómez, Claudia, Jofré, Paula, Vitali, Sara, Casamiquela, Laia, Soubiran, Caroline, Heiter, Ulrike, Blanco-Cuaresma, Sergi
Format: Preprint
Published: 2026
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author Hernández-Araya, Ivanna
Aguilera-Gómez, Claudia
Jofré, Paula
Vitali, Sara
Casamiquela, Laia
Soubiran, Caroline
Heiter, Ulrike
Blanco-Cuaresma, Sergi
author_facet Hernández-Araya, Ivanna
Aguilera-Gómez, Claudia
Jofré, Paula
Vitali, Sara
Casamiquela, Laia
Soubiran, Caroline
Heiter, Ulrike
Blanco-Cuaresma, Sergi
contents In the era of large Milky Way spectroscopic surveys, calibrating and standardizing stellar parameters and abundance measurements is crucial. The Gaia benchmark stars (GBS) are key references points characterized by well-defined parameters derived from fundamental relations independent of spectroscopy. We analyze 30 GBS with spectra data at three different resolutions. Our goal is to evaluate the impact of spectral resolution on the measurements of the stellar parameters and chemical abundances. We also present a line selection suitable for both metal-poor and metal-rich stars. We used R~190000 (R190), R~42000 (R42), R~28 000 (R28), and R190 degraded to R28 (R190-R28) spectral data to measure abundances with synthetic fitting and equivalent widths (EW) methods, testing the needed resolution to obtain consistent results. Our comparative analysis between R28 and R190-R28 shows that gaps in wavelength coverage can lead to discrepancies in the derived stellar parameters, particularly log g. These effects are not primarily driven by resolution, but rather by the limited spectral coverage and line availability. We find overall similar abundance, emphasizing the importance of line selection for spectroscopic studies. However, some elements (e.g, Ti II, Sc II) show larger discrepancies, possibly due to blending that becomes more pronounced as resolution decreases or is HFS-sensitive. Our comparative analysis shows that the abundances for Fe I, Ni I, Ti I, and Si I present less scatter across all resolutions, including R28. Our findings indicate that for some elements, synthetic fitting and the EW method give similar abundances, especially at the highest resolution. However, we also find that the highest resolution is not always essential for chemical abundance measurements. Our results provide practical guidelines for upcoming large surveys to reconstruct the chemical history of the Milky Way.
format Preprint
id arxiv_https___arxiv_org_abs_2605_25912
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Gaia FGK Benchmark Stars: Impact of Spectral Resolution on Stellar Abundances
Hernández-Araya, Ivanna
Aguilera-Gómez, Claudia
Jofré, Paula
Vitali, Sara
Casamiquela, Laia
Soubiran, Caroline
Heiter, Ulrike
Blanco-Cuaresma, Sergi
Solar and Stellar Astrophysics
Astrophysics of Galaxies
In the era of large Milky Way spectroscopic surveys, calibrating and standardizing stellar parameters and abundance measurements is crucial. The Gaia benchmark stars (GBS) are key references points characterized by well-defined parameters derived from fundamental relations independent of spectroscopy. We analyze 30 GBS with spectra data at three different resolutions. Our goal is to evaluate the impact of spectral resolution on the measurements of the stellar parameters and chemical abundances. We also present a line selection suitable for both metal-poor and metal-rich stars. We used R~190000 (R190), R~42000 (R42), R~28 000 (R28), and R190 degraded to R28 (R190-R28) spectral data to measure abundances with synthetic fitting and equivalent widths (EW) methods, testing the needed resolution to obtain consistent results. Our comparative analysis between R28 and R190-R28 shows that gaps in wavelength coverage can lead to discrepancies in the derived stellar parameters, particularly log g. These effects are not primarily driven by resolution, but rather by the limited spectral coverage and line availability. We find overall similar abundance, emphasizing the importance of line selection for spectroscopic studies. However, some elements (e.g, Ti II, Sc II) show larger discrepancies, possibly due to blending that becomes more pronounced as resolution decreases or is HFS-sensitive. Our comparative analysis shows that the abundances for Fe I, Ni I, Ti I, and Si I present less scatter across all resolutions, including R28. Our findings indicate that for some elements, synthetic fitting and the EW method give similar abundances, especially at the highest resolution. However, we also find that the highest resolution is not always essential for chemical abundance measurements. Our results provide practical guidelines for upcoming large surveys to reconstruct the chemical history of the Milky Way.
title Gaia FGK Benchmark Stars: Impact of Spectral Resolution on Stellar Abundances
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2605.25912