2020/12/11 by Devesh P. Sariya, Ing-Guey Jiang, M. D. Sizova +7
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Diagram #Limiting #Open cluster #Orbit (dynamics) #Range (aeronautics) #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.3847/1538-3881/abd31d
36 pages, 15 figures. Original submission on 25th June 2020 and accepted for the publication by The Astronomical Journal (AJ) on 10th December 2020
arxiv created 2020/12/11 · openalex created_date 2020/12/21 · openalex publication_date 2021/02/04 · arxiv updated 2021/02/10 · openalex updated_date 2026/08/05
Abstract We present an investigation of NGC 2158 using Gaia DR2 data. We identified 800 most likely cluster members with membership probability higher than 90%. The mean proper motions of this object are determined as ( μ x = −0.203 ± 0.003, μ y = −1.99 ± 0.004) mas yr −1 . The limiting radius, log(age), and distance of the cluster are obtained as 23.5 arcmin, 9.38 ± 0.04 Gyr, and 4.69 ± 0.22 kpc, respectively. The overall mass function slope (0.93 ± 0.14) is flatter than the Salpeter value (1.35) within the mass range of 1.17–1.44 M ⊙ . This cluster also shows the mass-segregation effect and our study demonstrates that NGC 2158 is a dynamically relaxed open cluster. Using the apex diagram (AD), the apex coordinates of the cluster are obtained in different ways and are examined using the ( μ U , μ T ) diagram. The best value of the apex coordinates is determined as A = 8724 ± 160, D = −3661 ± 530. We also determined the orbit of the cluster and found that NGC 2158 moves almost in the solar antapex direction. The resulting spatial velocity of NGC 2158 is 51 km s −1 . A significant oscillation along the Z -coordinate up to 529 pc is detected. Various scenarios regarding the origin of this cluster are also discussed.