Revisiting the Galactic age-metallicity relation from wide white dwarf-main-sequence binaries

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Autori principali: Rebassa-Mansergas, Alberto, Tejero-Gómez, Iset, Raddi, Roberto
Natura: Preprint
Pubblicazione: 2026
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author Rebassa-Mansergas, Alberto
Tejero-Gómez, Iset
Raddi, Roberto
author_facet Rebassa-Mansergas, Alberto
Tejero-Gómez, Iset
Raddi, Roberto
contents The age-metallicity relation (AMR) is a fundamental observational constraint for understanding the chemical evolution of the Galaxy. As reliable cosmochronometers, white dwarfs in binary systems with main sequence companions (WD+MS binaries) provide excellent laboratories to study this relation, since both components are expected to be coeval. We construct a sample of widely separated WD+MS binaries using data from the third data release of the Gaia mission in order to investigate the AMR of the Galactic disk. The sample is identified using photometric measurements and parallaxes of both components. White dwarf ages are derived by interpolating their Gaia absolute G magnitudes and BP-RP colours within state-of-the art white dwarf evolutionary sequences. We compile publicly available [Fe/H] abundances for the main sequence companions from the literature and combine them using different statistical approaches to obtain representative metallicity values for each system. We derive the AMR from several sub-samples of WD+MS that use independent measurements of [Fe/H] abundances and consistently find a large dispersion in [Fe/H] at all ages. This behaviour agrees with previous determinations of the AMR based on both WD+MS binaries and samples of isolated stars. Our results reinforce the observational evidence that the AMR in the Galactic disk exhibits substantial intrinsic scatter, likely reflecting the combined effects of multiple mechanisms such as radial migration, inhomogeneous chemical enrichment, and variations in the star formation history.
format Preprint
id arxiv_https___arxiv_org_abs_2604_15939
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Revisiting the Galactic age-metallicity relation from wide white dwarf-main-sequence binaries
Rebassa-Mansergas, Alberto
Tejero-Gómez, Iset
Raddi, Roberto
Solar and Stellar Astrophysics
Astrophysics of Galaxies
The age-metallicity relation (AMR) is a fundamental observational constraint for understanding the chemical evolution of the Galaxy. As reliable cosmochronometers, white dwarfs in binary systems with main sequence companions (WD+MS binaries) provide excellent laboratories to study this relation, since both components are expected to be coeval. We construct a sample of widely separated WD+MS binaries using data from the third data release of the Gaia mission in order to investigate the AMR of the Galactic disk. The sample is identified using photometric measurements and parallaxes of both components. White dwarf ages are derived by interpolating their Gaia absolute G magnitudes and BP-RP colours within state-of-the art white dwarf evolutionary sequences. We compile publicly available [Fe/H] abundances for the main sequence companions from the literature and combine them using different statistical approaches to obtain representative metallicity values for each system. We derive the AMR from several sub-samples of WD+MS that use independent measurements of [Fe/H] abundances and consistently find a large dispersion in [Fe/H] at all ages. This behaviour agrees with previous determinations of the AMR based on both WD+MS binaries and samples of isolated stars. Our results reinforce the observational evidence that the AMR in the Galactic disk exhibits substantial intrinsic scatter, likely reflecting the combined effects of multiple mechanisms such as radial migration, inhomogeneous chemical enrichment, and variations in the star formation history.
title Revisiting the Galactic age-metallicity relation from wide white dwarf-main-sequence binaries
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2604.15939