The Shape Evolution of Galactic Open Clusters from Observations under Galactic External Forces
Year: 2017
Type: article
Abstract: ABSTRACT We present the Galactic characteristics of 154 open clusters using the stellar statistics method with data from the WEBDA database. We find that all clusters in our sample are elongated in shape, which indicates that the spherical clusters are stretched out to be ellipsoid as a function of age . By dividing a cluster into a central core and an outer part, we have computed the apparent ellipticities of these two parts respectively. The scale relations between ellipticities and age indicate that the outer parts of open clusters become more elliptical while the central cores remain circular. We suppose that the outer parts become more elliptical because they are more subjected to the external forces, e.g., Galactic differential rotation, while the central cores form a circular shape under the domination of stellar dynamics. We have also performed an analysis of the crucial influence of cluster mass and location on its shape.
Source: The Astronomical Journal
Authors: Meng Zhai, Helmut Abt, Gang Zhao, Chengdong Li
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2577071678