J/other/JKOAS/52.145 207 new open star clusters from Gaia DR2 (Sim+, 2019)
207 New Open Star Clusters within 1 kpc from Gaia Data Release 2.
Sim G., Lee S.H., Ann H.B., Kim S.
<Journal of the Korean Astronomical Society, 52, 145 (2019)>
=2019JKoAS..52..145S 2019JKoAS..52..145S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Proper motions ; Stars, distances ; Optical
Keywords: open clusters and associations: general - catalogs -
methods: data analysis
Abstract:
We conducted a survey of open clusters within 1 kpc from the Sun using
the astrometric and photometric data of the Gaia Data Release 2. We
found 655 cluster candidates by visual inspection of the stellar
distributions in proper motion space and spatial distributions in l-b
space. All of the 655 cluster candidates have a well defined
main-sequence except for two candidates if we consider that the main
sequence of very young clusters is somewhat broad due to differential
extinction. Cross-matching of our 653 open clusters with known open
clusters in various catalogs resulted in 207 new open clusters. We
present the physical properties of the newly discovered open clusters.
The majority of the newly discovered open clusters are of young to
intermediate age and have less than ∼50 member stars.
Description:
We visually found 655 clusters within 1kpc from the Sun using the
astrometric (proper motion, position, parallax) and photometric data
of Gaia DR2, exploiting the fact that stars bound together in a
cluster have similar proper motions and are spatially clustered. We
used only stars brighter than G=18 to reduce contamination by field
stars caused by the fact that measurement errors increase as the
brightness of stars decreases.
We applied mean-shift and GMM analysis to identify clusters in
proper motion space and spatial distributions. We derived cluster
parameters such as the radii in which cluster stars are located in
proper motion space (rPM ) and l-b space (rGMM ) iteratively. We
validated cluster candidates by comparing their CMDs with
PARSEC Z=0.02 isochrones, which resulted in confirmation of 653 open
clusters from the 655 visually identified cluster candidates. We
cross-matched all 655 visually identified cluster candidates with
previous catalogs. We found 207 new open clusters among the 653
clusters that pass CMD validation. Some of the new open clusters might
actually be associations or small stellar aggregations given the small
numbers of member stars.
We present the physical parameters of the 207 new clusters in a
catalog that provides Galactic coordinates, mean proper motions,
parallaxes, rGMM, rc, numbers of member stars within rGMM, and
ages.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 89 207 Physical parameters of newly discovered open clusters
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Cluster UPK identifier (UPK NNN) (1)
10- 15 F6.2 deg GLON Galactic longitude
17- 22 F6.2 deg GLAT Galactic latitude
24- 29 F6.2 mas/yr pmRA* Proper motion along RA, pmRA*cosDE
31- 34 F4.2 mas/yr e_pmRA* Proper motion along RA, pmRA*cosDE, error
36- 41 F6.2 mas/yr pmDE Proper motion along DE
43- 46 F4.2 mas/yr e_pmDE Proper motion along DE error
48- 51 I4 pc Dist Distance
53- 54 I2 pc e_Dist Distance error
56- 61 F6.2 arcmin rGMM GMM cluster radius
63- 68 F6.2 arcmin rc King profile core radius
70- 73 F4.2 arcmin e_rc King profile core radius error
75- 77 I3 --- N Number of stars within the best-fit ellipse
79- 84 F6.2 --- Nc Number of member stars corrected for the
incompleteness due to the magnitude cut at
G=18
86- 89 F4.2 [yr] logAge Cluster age
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Note (1): UPK stands for the names of the authors' institutions:
Ulsan Science High School, Pusan National University, Korea Astronomy and
Space Science Institute.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 25-Jul-2025