J/A+A/693/A218 Binary and grouped open clusters (Palma+, 2025)
Binary and grouped open clusters: A new catalogue.
Palma T., Coenda V., Baume G., Feinstein C.
<Astron. Astrophys. 693, A218 (2025)>
=2025A&A...693A.218P 2025A&A...693A.218P (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open
Keywords: catalogs - open clusters and associations: general
Abstract:
Understanding the formation and evolution of star clusters in the
Milky Way requires precise identification of clusters that form binary
or multiple systems. Such systems offer valuable insight into the
dynamical processes and interactions that influence cluster evolution.
This study aims to detect and classify star clusters in the Milky Way
that are part of double or multiple systems. Specifically, we seek to
detect clusters that form gravitationally bound pairs or groups of
clusters and distinguish between different types of interactions based
on their physical properties and spatial distributions.
We used an extensive star cluster database which includes 7167
clusters. By estimating the tidal forces acting on each cluster
through the tidal factor and considering only close neighbours (within
50pc), we identified a total of 2170 star clusters forming part of
double or multiple systems. Pairs were classified as binaries, capture
pairs, or optical pairs based on proper motion distributions, cluster
ages, and colour-magnitude diagrams.
Our analysis identified 617 paired systems, and they were successfully
classified using our scheme. Additionally, we found 261 groups of star
clusters with three or more members, providing further evidence of the
presence of multiple systems within the Milky Way that exhibit
significant tidal interactions.
The method we present provides an improved approach for identifying
star clusters that share the same spatial volume and experience
notable tidal interactions.
Description:
We have identified star clusters in the Milky Way as part of double or
multiple systems by estimating the tidal forces acting on each
cluster, and considering only close neighbours (within 50pc). We used
the star cluster database of Hunt & Reffert (2023A&A...673A.114H 2023A&A...673A.114H, Cat.
J/A+A/673/A114, 2024A&A...686A..42H 2024A&A...686A..42H, Cat. J/A+A/686/A42) and
identified 617 paired systems, which were classified as binaries (B),
Ccapture pairs (C), or optical pairs (O/Oa) based on proper motion
distributions, cluster ages, and color-magnitude diagrams.
Additionally, we found 261 groups of star clusters, each with three or
more members.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 104 1234 Binary system candidates
table3.dat 83 936 Multiple system candidates
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See also:
J/A+A/673/A114 : Improving the open cluster census. II. (Hunt+, 2023)
J/A+A/686/A42 : Improving the open cluster census. III. (Hunt+, 2024)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Pair Pair identification
6- 22 A17 --- Cluster Star cluster name
24- 27 I4 --- HR24 HR24 internal ID (G1)
32- 38 F7.3 deg RAdeg Right ascension (J2000)
40- 46 F7.3 deg DEdeg Declination (J2000)
48 A1 --- Kind Object type estimated by HR24 (G1)
52- 58 F7.2 pc2/Msun TF Tidal factor
60- 67 F8.2 Myr Age50 ?=- Median age
70- 74 F5.2 --- MA/MB Mass ratio of the pair clusters
80- 87 F8.2 Myr DeltaAge50 ?=- Median age difference of the
pair clusters
93- 97 A5 --- PMcompat [false/true ] Compatibility in proper motions
103-104 A2 --- BCO Pair classification
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Group Pair identification
6- 25 A20 --- Cluster Star cluster name
27- 30 I4 --- HR24 HR24 internal ID (G1)
35- 41 F7.3 deg RAdeg Right ascension (J2000)
43- 49 F7.3 deg DEdeg Declination (J2000)
51 A1 --- Kind Object type estimated by HR24 (G1)
55- 61 F7.2 pc+2/Msun TF Tidal factor
63- 69 F7.2 Myr Age50 Median age
70- 81 A12 --- Ref Previous references (2)
83 I1 --- Ncls Number of clusters in each group
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Note (2): References as follows:
a = Liu & Pang, 2019ApJS..245...32L 2019ApJS..245...32L, Cat. J/ApJ/245/32
b = Piecka & Paunzen, 2021A&A...649A..54P 2021A&A...649A..54P
c = Conrad et al., 2017A&A...600A.106C 2017A&A...600A.106C, Cat. J/A+A/600/A106
d = Soubiran et al., 2019A&A...623C...2S 2019A&A...623C...2S, Cat. J/A+A/619/A155
e = Casado, 2021ARep...65..755C 2021ARep...65..755C
f = Song et al., 2022A&A...666A..75S 2022A&A...666A..75S
g = Subramaniam et al., 995 (1995A&A...302...86S 1995A&A...302...86S
h = Casado, 2022Univ....8..368C 2022Univ....8..368C
i = de la Fuente Marcos & de la Fuente Marcos, 2009A&A...500L..13D 2009A&A...500L..13D
j = Pavlovskaya & Filippova, 1989SvA....33....6P 1989SvA....33....6P
k = Angelo et al., 2022MNRAS.510.5695A 2022MNRAS.510.5695A
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Global notes:
Note (G1): Star cluster ID and type from Hunt & Reffert (2024A&A...686A..42H 2024A&A...686A..42H,
Cat. J/A+A/686/A42)
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Acknowledgements:
Tali Palma, tpalma(at)unc.edu.ar
(End) Tali Palma [OAC-UNC], Patricia Vannier [CDS] 30-Dec-2024