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. =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: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 115 265 The parameters of 265 open clusters in this paper -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Acknowledgements: Yu Zhang, zhy(at)xao.ac.cn ================================================================================ (End) Patricia Vannier [CDS] 27-May-2021