2018/10/31 by Gaurav Singh, R. K. S. Yadav · 8 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Blue straggler #Cluster (spacecraft) #Globular cluster #Mass segregation #Physics #RADIUS #Star cluster #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty2961
published in Monthly Notices of the Royal Astronomical Society 482(4), 4874-4882 (Oxford University Press) · 9 pages, 11 figures, 2 tables, Accepted in Monthly Notices of the Royal Astronomical Society Main Journal
openalex publication_date 2018/10/31 · arxiv created 2018/11/01 · arxiv updated 2018/11/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the dynamical status of the Galactic globular cluster NGC 6656 using the spatial distribution of blue straggler stars (BSSs). A combination of multi-wavelength high-resolution space- and ground-based data are used to cover a large cluster region. We determine the centre of gravity (Cgrav) and construct the projected density profile of the cluster using the probable cluster members selected from the Hubble Space Telescope and Gaia Data Release 2 proper-motion data sets. The projected density profile in the investigated region is nicely reproduced by a single-mass King model, with core (rc) and tidal (rt) radii of 75″.2 ± 3″.1 and 35′.6 ± 1′.1 respectively. In total, 90 BSSs are identified on the basis of proper-motion data in the region of radius 625″. The average mass of the BSSs is determined as 1.06 ± 0.09 M|\odot| and with an age range of 0.5 to 7 Gyr. The BSS radial distribution shows a bimodal trend, with a peak in the centre, a minimum at r ∼ rc and a rising tendency in the outer region. The BSS radial distribution shows a flat behaviour in the outermost region of the cluster. We also estimate the |A+rh| parameter as an alternative indicator of the dynamical status of the cluster; this is found to be 0.038 ± 0.016. Based on the radial distribution and |A+rh| parameter, we conclude that NGC 6656 is an intermediate dynamical age cluster.