A comprehensive analysis of NGC 2158 in Gaia era: photometric parameters, apex and orbit

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 (mu_{x}=-0.203 \pm 0.003, mu_{y}=-1.99 \pm 0.004) mas yr^{-1}. The limiting radius, log(age), and distance of the cluster are obtained as 23.5 arcmin, 9.38 \pm 0.04 Gyr and 4.69 \pm 0.22 kpc, respectively. The overall mass function slope (0.93 \pm 0.14) is flatter than the Salpeter value (1.35) within the mass range 1.17-1.44 M_\odot. This cluster also shows the mass-segregation effect and our study demonstrates that NGC 2158 is a dynamically relaxed open cluster. Using the AD-diagram, the apex coordinates of the cluster are obtained in different ways and examined using (μ_{U},μ_{T}) diagram. The best value of apex coordinates is determined as A=87.24^\circ \pm 1.60^\circ, D=-36.61^\circ \pm 5.30 ^\circ. 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 oscillations along the Z-coordinate up to 529~pc is detected. Various scenarios regarding the origin of this cluster are also discussed.

36 pages, 15 figures. Original submission on 25th June 2020 and accepted for the publication by The Astronomical Journal (AJ) on 10th December 2020

References in corpus (13)

• galpy: A Python Library for Galactic Dynamics
• Painting a portrait of the Galactic disc with its stellar clusters
• Age determination for 269 $Gaia$ DR2 Open Clusters
• Constraining the thermally-pulsing asymptotic giant branch phase with resolved stellar populations in the Small Magellanic Cloud
• Ground-Based CCD Astrometry with Wide Field Imagers. I. [Observations just a few years apart allow decontamination of field objects from members in two Globular clusters.]
• Ground-based CCD astrometry with wide field imagers. II. A star catalogue for M67: [email protected] MPG/ESO astrometry, FLAMES@VLT radial velocities
• Discovery and astrophysical properties of Galactic open clusters in dense stellar fields using Gaia DR2
• Variable stars in two open clusters within the Kepler 2-Campaign-0 field: M 35 and NGC 2158
• Blue Straggler Populations of Seven Open Clusters with Gaia DR2
• An investigation of poorly studied open cluster NGC 4337 using multi-color photometric and Gaia DR2 astrometric data
• Structure of the outer Galactic disc with Gaia-DR2
• Apex determination and detection of stellar clumps in the open cluster M 67
• A proper motions study of the globular cluster NGC 3201

Cited by in corpus (3)

• Multi-colour photometry and Gaia EDR3 astrometry of two couples of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324)
• A deep investigation of two poorly studied open clusters Haffner 22 and Melotte 71 in Gaia era
• A Gaia based photometric and kinematic analysis of the old open cluster King 11