J/A+A/693/A125 Morphological stability of nearby open clusters (Hu+, 2025)
3D projection analysis: Characterizing the morphological stability of nearby
open clusters.
Hu Q., Qin S., Luo Y., Li Y.
<Astron. Astrophys. 693, A125 (2025)>
=2025A&A...693A.125H 2025A&A...693A.125H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, nearby
Keywords: open clusters and associations: general
Abstract:
The study of open cluster morphology is pivotal for exploring their
formation and evolutionary processes.
We manage to assess the morphological stability of 105 nearby open
clusters within tidal radii on the X-Y, X-Z, and Y-Z planes of the
heliocentric Cartesian coordinate system, utilizing member catalogs
from the literature. Meanwhile, we also delve into factors potentially
impacting the clusters' morphological stability on these projection
planes.
We used the rose diagram method by constructing the 3D projected
morphology of sample clusters to quantify the morphological stability
of their 3D projected morphology.
Our analysis indicates there is a demonstrated linear positive
correlation between the number of sample clusters' member stars
within tidal radii and their morphological stability in different 3D
projection planes. This may suggest that the more member stars there
are within the tidal radius of a cluster, the stronger its own
gravitational binding capacity is, resulting in strong morphological
stability. We find a direct link between the clusters' morphological
stabilities in the X-Z plane within tidal radii and their velocity
dispersion in the same plane, suggesting that the morphological
stabilities in the X-Z plane may be dependent on internal dynamics.
Moreover, the morphological stability of the clusters' 3D projection
is influenced by their spatial positions along the Y axis, but not
linearly, indicating that the environmental changes at the clusters'
location may affect their morphological stability. Likewise, specific
external forces can have an effect on their morphological stability.
This research introduces a novel perspective for understanding the
morphological stability of open clusters, with a particular focus on
their 3D projected morphologies.
Description:
In this study, we employed the rose diagram method to quantify the 3D
projected morphology of 105 nearby open clusters selected from the
literature. Additionally, we defined the morphological stability of
these clusters' 3D projected distributions within tidal radii for
the first time and investigated some factors that may influence this
stability in different projected planes.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 75 105 The morphological stability and position
parameters of the sample clusters
tablea2.dat 80 105 The external forces and fundamental parameters
of the sample clusters
tablea3.dat 96 105 The velocity dispersion and other parameters
of the sample clusters
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Cluster name
20- 26 F7.2 pc X Cluster X coordinate within heliocentric
Cartesian coordinates frame
29- 35 F7.2 pc Y Cluster Y coordinate within heliocentric
Cartesian coordinates frame
38- 44 F7.2 pc Z Cluster Z coordinate within heliocentric
Cartesian coordinates frame
47- 50 F4.2 --- Scorexy/Souterxy Morphological stability on the X-Y
projection plane
52- 55 F4.2 --- e_Scorexy/Souterxy Error of morphological stability on the
X-Y projection plane
57- 60 F4.2 --- Scorexz/Souterxz Morphological stability on the X-Z
projection plane
62- 65 F4.2 --- e_Scorexz/Souterxz Error of morphological stability on the
X-Z projection plane
67- 70 F4.2 --- Scoreyz/Souteryz Morphological stability on the Y-Z
projection plane
72- 75 F4.2 --- e_Scoreyz/Souteryz Error of morphological stability on the
Y-Z projection plane
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Cluster name
20- 25 F6.1 --- Nrt Number of members within the tidal radius
27- 30 F4.1 --- e_Nrt Error of number of members within the
tidal radius
32- 37 F6.2 pc Rt Tidal radii of the sample clusters
39- 43 F5.2 pc e_Rt Error of tidal radii of the sample clusters
46- 52 F7.2 --- FR Radial force (in 2pi*GM/pc2 unit)
55- 58 F4.2 --- e_FR Error of radial force (in 2pi*GM/pc2 unit)
60- 65 F6.2 --- Fz Vertical force (in 2pi*GM/pc2 unit)
67- 70 F4.2 --- e_Fz Error of vertical force (in 2pi*GM/pc2 unit)
72- 75 F4.2 --- E Orbital eccentricity
77- 80 F4.2 --- e_E Error of orbital eccentricity
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Cluster name
20- 24 F5.2 km/s sigmaVxy Velocity dispersion of sample clusters in the
X-Y projected plane
27- 30 F4.2 km/s e_sigmaVxy Error of velocity dispersion of sample
clusters in the X-Y projected plane
34- 38 F5.2 km/s sigmaVxz Velocity dispersion of sample clusters in the
X-Z projected plane
41- 44 F4.2 km/s e_sigmaVxz Error of velocity dispersion of sample
clusters in the X-Z projected plane
48- 52 F5.2 km/s sigmaVyz Velocity dispersion of sample clusters in the
Y-Z projected plane
55- 58 F4.2 km/s e_sigmaVyz Error of velocity dispersion of sample
clusters in the Y-Z projected plane
62- 64 I3 --- NRv Number of members with radial velocities for
calculation of velocity dispersion of
sample clusters
68- 71 F4.2 --- rxy Radii of the central core regions of sample
clusters on the X-Y projection plane
73- 76 F4.2 --- e_rxy Error of radii of the central core regions of
sample clusters on the X-Y projection plane
78- 81 F4.2 --- rxz Radii of the central core regions of sample
clusters on the X-Z projection plane
83- 86 F4.2 --- e_rxz Error of radii of the central core regions of
sample clusters on the X-Z projection plane
88- 91 F4.2 --- ryz Radii of the central core regions of sample
clusters on the Y-Z projection plane
93- 96 F4.2 --- e_ryz Error of radii of the central core regions of
sample clusters on the Y-Z projection plane
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Acknowledgements:
Qingshun Hu, qingshun0801(at)163.com
(End) Qingshun Hu [Nanchong, China], Patricia Vannier [CDS] 16-Dec-2024