J/other/RAA/24.E5014 83 new open clusters (Lu+, 2024)
BSEC method for unveiling open clusters and its application to Gaia DR3:
83 new clusters.
Lu Z.M., Mao C.Y.
<Res. Astron. Astrophys., 24, 055014 (2024)>
=2024RAA....24e5014L 2024RAA....24e5014L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Optical ; Proper motions
Keywords: Galaxy: stellar content -
(Galaxy:) open clusters and associations: general -
stars: fundamental parameters
Abstract:
Open clusters (OCs) are common in the Milky Way, but most of them
remain undiscovered. There are numerous techniques, including some
machine-learning algorithms, available for the exploration of OCs.
However, each method has its limitations and therefore, different
approaches to discovering OCs hold significant values. We develop a
comprehensive approach method to automatically explore the data space
and identify potential OC candidates with relatively reliable
membership determination. This approach combines the techniques of
Hierarchical Density-Based Spatial Clustering of Applications with
Noise, Gaussian mixture model, and a novel cluster member
identification technique, color excess constraint. The new method
exhibits efficiency in detecting OCs while ensuring precise
determination of cluster memberships. Because the main feature of this
technique is to add an extra constraint (EC) for the members of
cluster candidates using the homogeneity of color excess, compared to
typical blind search codes, it is called Blind Search-Extra Constraint
(BSEC) method. It is successfully applied to the Gaia Data Release 3,
and 83 new OCs are found, whose color-magnitude diagrams (CMDs) are
fitted well to the isochrones. In addition, this study reports 621 new
OC candidates with discernible main sequence or red giant branch. It
is shown that BSEC technique can discard some false negatives of
previous works, which takes about three percentage of known clusters.
It shows that as an EC, the color excess (or two-color) constraint is
useful for removing fake cluster member stars from the clusters that
are identified from the positions and proper motions of stars, and
getting more precise CMDs, when differential reddening of member stars
of a cluster is not large (e.g., {DELTA}E(GBP-GRP)<0.5mag). It makes
the CMDs of 15% clusters clearer (in particular for the region near
turnoff) and therefore is helpful for CMD and stellar population
studies. Our result suggests that the color excess constraint is more
appropriate for clusters with small differential reddening, such as
globular clusters or older OCs, and clusters that the distances of
member stars cannot be determined accurately.
Description:
This work uses the data of the latest release of Gaia, i.e., Gaia DR3
(Gaia Collaboration et al. 2023A&A...674A...1G 2023A&A...674A...1G, Cat. I/355).
It finally found 83 new OCs with CMDs similar to the isochrones of
stellar populations and 621 new candidates with rough CMDs.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table56.dat 72 83 Astrometric parameters of newly found OCs that
the CMDs can be fitted well by isochrones
good.dat 23 83 New OC that the CMDs can be fitted well by
isochrones list
rough.dat 23 621 New OC candidates with discernible main
sequence or red giant branch list
matched.dat 23 2941 Known matched OC candidates list
unmatch.dat 64 2105 Known unmatched clusters list
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: table56.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- NOC [1/83] Sequential number
4- 10 F7.3 deg RAdeg Right ascension (J2000)
12- 16 F5.3 deg e_RAdeg Right ascension uncertainty
18- 24 F7.3 deg DEdeg Declination (J2000)
26- 30 F5.3 deg e_DEdeg Declination
32- 36 F5.3 mag plx Parallax
38- 42 F5.3 mag e_plx Parallax uncertainty
44- 49 F6.3 mas/yr pmRA Proper motion along RA
51- 55 F5.3 mas/yr e_pmRA Proper motion along RA uncertainty
57- 62 F6.3 mas/yr pmDE Proper motion along DE
64- 68 F5.3 mas/yr e_pmDE Proper motion along DE uncertainty
70- 72 I3 --- N Number of member stars
--------------------------------------------------------------------------------
Byte-by-byte Description of file: good.dat rough.dat matched.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Name
9- 15 F7.3 deg GLON Galactic longitude
17- 23 F7.3 deg GLAT Galactic latitude
--------------------------------------------------------------------------------
Byte-by-byte Description of file: unmatch.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name Cluster name
25- 43 A19 --- Ref Reference (BibCode)
48- 55 F8.4 deg GLON Galactic longitude
57- 64 F8.4 deg GLAT Galactic latitude
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Aug-2025