J/A+A/689/A18 Gaia Galactic open clusters located within 1kpc (Alfonso+, 2024)
Exploring Galactic open clusters with Gaia.
I. An examination in the first kiloparsec.
Alfonso J., Garcia-Varela A., Vieira K.
<Astron. Astrophys. 689, A18 (2024)>
=2024A&A...689A..18A 2024A&A...689A..18A (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Optical ; Proper motions ;
Parallaxes, trigonometric
Keywords: open clusters and associations: general - methods: data analysis -
Galaxy: disk
Abstract:
Since the first publication of the Gaia catalogue a new view of our
Galaxy has arrived. Its astrometric and photometric information has
improved the precision of the physical parameters of open star
clusters obtained from them.
Using the Gaia DR3 catalogue, we aim to find physical stellar members
including faint stars for 370 Galactic open clusters located within
1kpc. We also estimate the age, metallicity, distance modulus and
extinction of these clusters.
We employ the HDBSCAN algorithm on both astrometric and photometric
data to identify members in the open clusters. Subsequently, we refine
the samples by eliminating outliers through the application of the
Mahalanobis metric utilizing the χ2 distribution at a confidence
level of 95%. Furthermore, we characterize the stellar parameters with
the PARSEC isochrones.
We obtain reliable star members for 370 open clusters with an average
parallax error of σπ=0.16mas. We identify about ∼40% more stars
in these clusters compared to previous work using the Gaia DR2
catalogue, including faint stars as new members with G≥17. Before
the clustering application we correct the parallax zero-point bias to
avoid spatial distribution stretching that may affect clustering
results. Our membership lists include merging stars identified by
HDBSCAN with astrometry and photometry. We note that the use of
photometry in clustering can recover up to 10% more stars in the
fainter limit than clustering based on astrometry only, this combined
with the selection of stars filtering them out by quality cuts
significantly reduces the number of stars with huge σπ. After
clustering, we estimate age, Z, and AV from the photometry of the
membership lists.
We have carried out a search to extent the membership list for 370
open clusters mainly on the Galactic plane in a neighborhood of 1kpc.
Our methodology provides a robust estimator for outliers
identification and also extends the membership lists to fainter stars
in most of the clusters. Our findings suggest the need to carefully
identify spurious sources that may affect clustering results.
Description:
In this paper we identify bona fide star members up to G=19.8 mag in
370 nearby open clusters using the Gaia DR3 catalogue. We employ the
HDBSCAN clustering algorithm on astrometry and photometry. Then, we
use the Mahalanobis metric to reduce outliers in the clusters.
Finally, we characterize the cluster parameters using BASE-9.
We present two tables.
clusters.dat: cluster parameters (Table 1)
members.dat: members of clusters in the main catalogue.
All columns come from Gaia DR3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 206 370 Cluster parameters (table 1)
members.dat 167 87708 Members of clusters in the main catalogue
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Cluster sequential number
5- 21 A17 --- Cluster Main accepted cluster name
23- 26 I4 --- Nstars [24/2520] Number of stars in the open cluster
28- 47 F20.16 deg RAdeg [] Mean Right Ascension (ICRS) at Ep=2016.0
49- 68 F20.16 deg DEdeg Mean Declination (ICRS) at Ep=2016.0
70- 89 F20.16 mas/yr pmRA Mean Proper motion in right ascension direction
91-110 F20.16 mas/yr pmDE Mean Proper motion in declination direction
112-129 F18.16 mas Plx Mean absolute stellar corrected parallax
131-147 F17.15 [yr] logAge Estimated age
149-167 F19.16 [-] Z Estimated metallicity
169-186 F18.16 mag AV Estimated extinction
188-206 F19.16 mag MOD Estimated distance modulus
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Byte-by-byte Description of file: members.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Cluster Cluster name
19- 37 I19 --- GaiaDR3 Gaia DR3 source ID
39- 58 F20.16 deg RAdeg [] Right Ascension (ICRS) at Ep=2016.0
60- 79 F20.16 deg DEdeg Declination (ICRS) at Ep=2016.0
81-103 E23.15 mas/yr pmRA Proper motion in right ascension direction
105-127 E23.15 mas/yr pmDE Proper motion in declination direction
129-147 F19.16 mas Plx Absolute stellar parallax
149-167 F19.16 mas PlxCorr Absolute stellar corrected parallax
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Acknowledgements:
Jeison Alfonso, je.alfonso1(at)uniandes.edu.co
(End) Patricia Vannier [CDS] 23-Jul-2024