J/A+A/703/A100 Open cluster parameters derived using Gaia XP (Nizovkina+, 2025)
Refining open cluster parameters with Gaia XP metallicities.
Nizovkina M., Larsen S.S., Brown A.G.A., Helmi A.
<Astron. Astrophys. 703, A100 (2025)>
=2025A&A...703A.100N 2025A&A...703A.100N (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Abundances, [Fe/H] ; Extinction ;
Stars, distances ; Stars, ages
Keywords: methods: statistical - open clusters and associations: general -
Galaxy: stellar content
Abstract:
Open clusters (OCs) are crucial objects for studying stellar evolution
and Galactic dynamics due to the shared origin and composition of the
stars within each cluster. The precision of cluster parameter
determination has significantly improved with the availability of
homogeneous photometric Gaia data; however, challenges such as
age-metallicity degeneracy and lack of spectroscopic observations
remain.
We investigate whether metallicities derived from low-resolution Gaia
XP spectra can be effectively used to break degeneracies and improve
the accuracy of OC parameter determinations.
We analysed 20 OCs using isochrone fitting methods on Gaia DR3
photometry and metallicity estimates from several Gaia XP-based
catalogues. We derived age, distance modulus, and extinction using the
Approximate Bayesian Computation (ABC).
We compared the parameter estimates to the values obtained in other
works through isochrone fitting with spectroscopically constrained
metallicities or through neural network techniques applied only to the
photometry. We found the systematic difference between Gaia XP derived
metallicities and those obtained from high-resolution spectroscopy to
be 0.1-0.15dex. We found a systematic age difference of
<0.03±0.13dex compared to isochrone fitting using high-resolution
spectroscopy, and <0.08±0.21dex compared to neural network-based
methods, and a median individual error of ∼0.065dex.
Despite their low resolution, Gaia XP metallicities effectively
constrain parameters of clusters lacking a well-populated RGB. When
used with stringent quality cuts and incorporated as priors, they
allow to determine ages comparable in precision to those based on
high-resolution spectroscopy and more precise than photometry-only
neural network methods. These results highlight the potential of Gaia
data for accurate cluster parameter analysis and detailed Galactic
studies without relying on traditional spectroscopy.
Description:
Cluster parameters AV, dm and log age derived using different [Fe/H]
priors.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb.dat 111 100 OC parameters derived in this study
(tables B1 and B2)
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/585/A150 : On the metallicity of open clusters. III. (Netopil+, 2016)
J/A+A/618/A93 : Gaia DR2 open clusters in the Milky Way (Cantat-Gaudin+, 2018)
J/A+A/623/A108 : Age of 269 GDR2 open clusters (Bossini+, 2019)
J/A+A/686/A42 : Improving the open cluster census. III. (Hunt+, 2024)
Byte-by-byte Description of file: tableb.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Cluster Cluster name
12- 23 F12.8 deg RAdeg Right ascension of densest point (ICRS)
at Ep=2016.0 (from Hunt et al.,
2024A&A...686A..42H 2024A&A...686A..42H, Cat. J/A+A/686/A42)
25- 36 F12.8 deg DEdeg Declination of densest point (ICRS)
at Ep=2016.0 (from Hunt et al.,
2024A&A...686A..42H 2024A&A...686A..42H, Cat. J/A+A/686/A42)
38- 41 A4 --- r_[Fe/H] Reference for the metallicity assumed (1)
43- 48 F6.3 [Sun] [Fe/H] Cluster metallicity assumed
50- 54 F5.3 [Sun] s_[Fe/H] ?=9.999 Standard deviation of [Fe/H]
derived from Gaia XP-based catalogues
56- 60 F5.3 mag AV Bayesian estimation of extinction in V band
62- 66 F5.3 mag AV16 16th percentile of extinction in V band
68- 72 F5.3 mag AV84 84th percentile of extinction in V band
74- 79 F6.3 mag DM Bayesian estimation of distance modulus
81- 86 F6.3 mag DM16 16th percentile of distance modulus
88- 93 F6.3 mag DM84 84th percentile of distance modulus
95- 99 F5.3 [yr] logAge Bayesian estimation of logarithm of cluster age
101-105 F5.3 [yr] logAge16 16th percentile of logarithm of cluster age
107-111 F5.3 [yr] logAge84 84th percentile of logarithm of cluster age
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Note (1): References as follows:
ARC = mean [Fe/H] derived from Andrae et al. (2023ApJS..267....8A 2023ApJS..267....8A)
ZGR = mean [Fe/H] derived from Zhang et al. (2023MNRAS.524.1855Z 2023MNRAS.524.1855Z)
FS = mean [Fe/H] derived from Fallows & Sanders (2024MNRAS.531.2126F 2024MNRAS.531.2126F)
None = [Fe/H] was a free fit parameter, and the 50th percentile of its PDF
is listed
HRS = [Fe/H] adopted from the high-quality spectroscopic sample of
Bossini et al. (2019A&A...623A.108B 2019A&A...623A.108B, Cat. J/A+A/623/A108),
based on Netopil et al., 2016A&A...585A.150N 2016A&A...585A.150N, Cat. J/A+A/585/A150
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Acknowledgements:
Mariya Nizovkina, m.nizovkina(at)astro.ru.nl
(End) Patricia Vannier [CDS] 22-Sep-2025