J/ApJ/912/5 Parameters of 265 open clusters (Hu+, 2021)
Deciphering star cluster evolution by shape morphology.
Hu Q., Zhang Y., Esamdin A., Liu J., Zeng X.
<Astrophys. J. 912, 5 (2021)>
=2021ApJ...912....5H 2021ApJ...912....5H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open
Keywords: open star clusters - star clusters
Abstract:
We analyze the morphological evolution of open clusters and provide
shape parameters for 265 open clusters. The results show that the
overall shape of sample clusters becomes more elliptical as they grow
older, while their core remains circular or slightly trending to
circular. There is a negative correlation of the ellipticities with
the number of members of the sample clusters. A significant negative
correlation between the overall ellipticities and masses is also
detected for the sample clusters with log(age/year)≥8, suggesting
that the overall shapes of the clusters are possibly influenced by the
number of members and masses, in addition to the external forces and
the surrounding environment. For most young sample clusters, the
radial stratification degree of the short-axis direction is greater
than that of the long, implying that the radial stratification degree
in the two directions within the young sample cluster may be unevenly
affected by an internal evolutionary process. Older sample clusters
exhibit lower stratification in the tangential direction, which
possibly means those clusters may continue to survive for a long time
at a low level of stratification. Our analysis shows that the overall
shape of the sample clusters may be more susceptible to the influence
of Galactic tides toward the Galactic center than the shear forces
embedded in Galactic differential rotation. By analyzing the
distribution of the ages and number of members of star clusters, we
suggest that NGC 6791 may originate from superclusters.
Description:
In this study, we use the member catalog of open clusters available in
the literature (Cantat-Gaudin et al., 2018, Cat. J/A+A/618/A93) to
give the shape parameters of 265 open clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 115 265 The parameters of 265 open clusters in this paper
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See also:
J/A+A/618/A93 : Gaia DR2 open clusters in the Milky Way (Cantat-Gaudin+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Cluster identifier
17- 23 F7.3 deg GLON Galactic longitude
25- 31 F7.3 deg GLAT Galactic latitude
33- 37 F5.3 [yr] logAge log cluster age
39- 44 F6.1 pc H Height from Galactic disk
46- 51 F6.1 --- Num Number of member stars in cluster
53- 57 F5.3 --- eCore Core ellipticity
59- 63 F5.3 --- e_eCore Uncertainty in eCore
65- 71 F7.3 deg qCore Core orientation
73- 77 F5.3 --- eAll Ellipticity of entire cluster
79- 83 F5.3 --- e_eAll Uncertainty in eAll
85- 91 F7.3 deg qAll Entire cluster orientation
93- 97 F5.3 --- aCore Core half-length
99-103 F5.3 --- bCore Core half-short axis
105-109 F5.3 --- aAll Entire cluster half-length
111-115 F5.3 --- bAll Entire cluster half-short axis
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Acknowledgements:
Yu Zhang, zhy(at)xao.ac.cn
(End) Patricia Vannier [CDS] 27-May-2021