A Comprehensive Study of Five Intermediate-age Pismis (2, 3, 7, 12, 15) Clusters Using Photometric and Astrometric Data from Gaia EDR3

Abstract

Open clusters are groups of stars that form simultaneously; hence, these are excellent probes to test theories of star formation, stellar evolution, and dynamics in the Milky Way disk. We carry out a detailed photometric and kinematic study of five poorly studied intermediate-age open clusters, Pismis 2 (Pi 2), Pismis 3 (Pi 3), Pismis 7 (Pi 7), Pismis 12 (Pi 12), and Pismis 15 (Pi 15), using the Gaia EDR3 database. By estimating the membership probabilities of stars, we recognized 635, 1488, 535, 368, and 494 most probable members for these clusters by using proper-motion and parallax data taken from Gaia EDR3. The radial density profiles of cluster members provide cluster radii of 4.′5–6.′5 for these clusters. Their ages range from 0.9 to 2.5 Gyr, and distances range, using parallax, from 2.15 to 5.10 kpc. The overall mass function slopes for main-sequence stars are found as 0.27 ± 0.16 (for 1.0–1.6 M ⊙ stars), 0.86 ± 0.27 (for 1.0–2.1 M ⊙ stars), 1.08 ± 0.32 (for 1.0–2.2 M ⊙ stars), 0.89 ± 0.38 (for 1.0–2.2 M ⊙ stars), and 1.07 ± 0.28 (for 1.0–2.1 M ⊙ stars) for clusters Pi 2, Pi 3, Pi 7, Pi 12, and Pi 15. Our obtained values of slopes are flatter in comparison with Salpeter’s value (x = 1.35) within uncertainty. The present study demonstrates that all these Pismis clusters are dynamically relaxed. We found that these objects follow a circular path around the Galactic center. We compute these clusters’ apex coordinates (A, D) and other kinematic parameters.

Exploring NGC 2345: A Comprehensive Study of a Young Open Cluster through Photometric and Kinematic Analysis

“…We used the membership determination method described in Balaguer-Núnez et al (1998) for the cluster NGC 2345. Many authors used this method in previous studies (Yadav et al 2013;Sharma et al 2020;Bisht et al 2021aBisht et al , 2021bBisht et al , 2022aBisht et al , 2022b. Proper-motion (PM) distribution is the unique identity of the stars or an excellent tool to separate the cluster members.…”

“…The proper motions of the stars in the cluster region reach the maximum value at (m a *, μ δ ) = (−1.34, 1.35) mas yr −1 . We have used the approach discussed in Bisht et al (2022a) to calculate the membership probability of the stars in the cluster region. We found the dispersion in PMs to be 0.08 mas yr −1 by using the cluster distance of 2.78 kpc and the radial-velocity dispersion of 1 km s −1 for open clusters (Girard et al 1989).…”

CCD UBV and Gaia DR3 Analyses of the Open Clusters King 6 and NGC 1605

“…The astrophysical parameters of OCs are commonly estimated simultaneously from isochrones fitted to the observed CMDs (Angelo et al 2021;Bisht et al 2022) and Bayesian statistics (von Hippel et al 2006;Bossini et al 2019). Large uncertainties in the derived reddening, metallicity, and hence age are driven by degeneracies between parameters in such simultaneous statistical solutions based on the comparison of stellar isochrones with photometric observations (Janes et al 2014).…”