J/A+A/692/A212 Metallicity of open clusters (Zhang+, 2024)
When LAMOST meets Gaia DR3: Exploring the metallicity of open clusters.
Zhang R., Wang G.-J., Lu Y.(L.), Guo S., Lucatello S., Fu X., Wang H.,
Wang L., Schiappacasse-Ulloa J., Chen J., Han Z.
<Astron. Astrophys. 692, A212 (2024)>
=2024A&A...692A.212Z 2024A&A...692A.212Z (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Radial velocities ; Optical ; Abundances, [Fe/H]
Keywords: stars: abundances - stars: evolution -
open clusters and association: general
Abstract:
Open clusters (OCs) are excellent probes as their age and abundance
can be tightly constrained, allowing us to explore
the distribution of metallicity and composition across the disk of the
Milky Way. By conducting a comprehensive analysis of the metallicity
of OCs, we can obtain valuable information about the history of their
chemical enrichment. Moreover, by observing stars in different regions
of the Milky Way, we can identify significant spatial structures in
their chemical composition and abundance. This enables us to
understand stellar birth radii through chemical tagging. Nevertheless,
it remains challenging to infer the original positions of OCs using
current data alone.
The aim of this study is to investigate the distribution of
metallicity in the solar neighborhood using a large dataset from Gaia
DR3 combined with LAMOST spectra. With accurate ages and metallicity
measurements, we can determine birth radii for the stars and attempt
to understand their migration pattern.
We chose a total of 1131 OCs within 3Kpc of the Sun from the Gaia DR3
and LAMOST DR8 low-resolution spectral database (R=1800). We used an
artificial neural network to correct the LAMOST data by incorporating
high-resolution spectral data from GALAH DR3 (R=28000). The average
metallicity of the OCs was determined based on the reliable [Fe/H]
values for their members. We then examined the distribution of
metallicity across different regions within the Galaxy and inferred
birth radii of the OCs from their age and metallicity.
The correction method presented here can partially eliminate the
systematic offset for LAMOST data. We discuss the metallicity trend as
a function of Galactocentric distance and the guiding radii. We also
compare these observational results with those from chemo-dynamic
simulations. Values derived from observational metallicity data are
slightly lower than predicted values when the uncertainties are not
considered. However, the metallicity gradients are consistent with
previous calculations. Finally, we investigated the birthplace of OCs
and find hints that the majority of OCs near the Sun have migrated
from the outer Galactic disk.
Description:
This study uses low-resolution spectra obtained from the LAMOST
to re-evaluate the metallicity abundance of over 1131 open 750
clusters (OCs) identified in the Gaia DR3 catalog (Cavallo et al.,
2024AJ....167...12C 2024AJ....167...12C, Cat. J/AJ/167/12). The selected OCs in this study
span an age range from a few million years to 9.5Gyr, with the
majority of OCs being younger than 600Myr. These samples are
primarily located in the solar neighborhood, covering a galactocentric
distance ranging from 4.68kpc to 16.7kpc.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 165 1131 Radial velocities for the OCs studied here
compared to those from the literature
tablea1.dat 180 1121 Basic information of OCs in the present samples
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
J/AJ/167/12 : Open cluster parameters with ANN (Cavallo+, 2024)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Cluster Name or identifier of the astronomical
cluster being studied
21- 22 I2 h RAh Right ascension of the cluster (ICRS)
24- 25 I2 min RAm Right ascension of the cluster (ICRS)
27- 31 F5.2 s RAs Right ascension of the cluster (ICRS)
33 A1 --- DE- Declination sign of the cluster (ICRS)
34- 35 I2 deg DEd Declination of the cluster (ICRS)
37- 38 I2 arcmin DEm Declination of the cluster (ICRS)
40- 44 F5.2 arcsec DEs Declination of the cluster (ICRS)
46- 65 F20.15 km/s RV-LRS ? Radial velocity measured using
low-resolution spectroscopy (LRS) LAMOST
67- 85 F19.15 km/s e_RV-LRS ? Uncertainty or error in the radial velocity
measurement from low-resolution
spectroscopy (LRS)
87-105 F19.15 km/s RV-HRS ? Radial velocity measured using
high-resolution spectroscopy (HRS) LAMOST
107-125 F19.15 km/s e_RV-HRS ? Uncertainty or error in the radial velocity
measurement from high-resolution
spectroscopy (HRS)
127-145 F19.15 km/s RV-GaiaDR3 ? Radial velocity obtained from the Gaia Data
Release 3 (Gaia DR3) measurements
147-165 F19.15 km/s e_RV-GaiaDR3 ? Uncertainty or error in the radial velocity
measurement from Gaia Data Release 3
(Gaia DR3)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Cluster Name or identifier of the astronomical
cluster being studied
21- 22 I2 h RAh Right ascension of the cluster (ICRS)
24- 25 I2 min RAm Right ascension of the cluster (ICRS)
27- 31 F5.2 s RAs Right ascension of the cluster (ICRS)
33 A1 --- DE- Declination sign of the cluster (ICRS)
34- 35 I2 deg DEd Declination of the cluster (ICRS)
37- 38 I2 arcmin DEm Declination of the cluster (ICRS)
40- 44 F5.2 arcsec DEs Declination of the cluster (ICRS)
46- 51 F6.3 kpc Rgc Galactocentric distance of the cluster
53- 69 F17.12 kpc.km/s Lz Vertical component of angular momentum about
the Z-axis (the axis perpendicular to the
galactic plane)
71- 87 F17.14 kpc Rguiding Guiding radius, which indicates the
effective distance from the center of the
cluster at which stars are significantly
influenced by the cluster's gravitational
field
89-100 F12.9 kpc Rbirth Birth radius, indicating the distance from
the center of the cluster where stars
formed
102-119 F18.15 --- [Fe/H]ANN Metallicity of the cluster as determined by
the ANN (Artificial Neural Network) method
121-137 F17.15 --- e_[Fe/H]ANN Uncertainty or error associated with the
[Fe/H]ANN metallicity measurement
139-159 E21.17 --- [Fe/H]MCMC Metallicity of the cluster determined using
Markov Chain Monte Carlo (MCMC) method
161-177 F17.15 --- e_[Fe/H]MCMC Uncertainty or error associated with the
[Fe/H]MCMC metallicity measurement
179-180 I2 --- Nmemb Number of stars or members within the
cluster used in the analysis
--------------------------------------------------------------------------------
Acknowledgements:
Ruyuan Zhang, ruyuan.zhang(at)studenti.unipd.it
(End) Patricia Vannier [CDS] 31-Oct-2024