English

Study of Open Star Clusters Using the Gaia DR3: I- Poorly Studied King 2 and King 5

Astrophysics of Galaxies 2025-03-25 v3 Solar and Stellar Astrophysics

Abstract

In this study, we utilize photometric and kinematic data from \textit{Gaia} DR3 and the {\sc ASteCA} package to analyze the sparsely studied open clusters, King 2 and King 5. For King 2, we identify 340 probable members with membership probabilities exceeding 50\%. Its mean proper motion components are determined as (μαcosδ, μδ)=(1.407±0.008,0.863±0.012)(\mu_\alpha\cos\delta,~\mu_\delta) = (-1.407 \pm 0.008, -0.863 \pm 0.012) mas yr1^{-1}, and its limiting radius is derived as 6.941.06+0.226.94_{-1.06}^{+0.22} arcminutes based on radial density profiles. The cluster has an estimated age of 4.80±0.304.80 \pm 0.30 Gyr, a distance of 6586±1646586 \pm 164 pc, and a metallicity of [Fe/H]=0.25\text{[Fe/H]} = -0.25 dex (z=0.0088z = 0.0088). We detect 17 blue straggler stars (BSSs) concentrated in its core, and its total mass is estimated to be 356±19 M356 \pm 19~M_{\odot}. The computed apex motion is (Ao, Do)=(142.61±0.08,63.58±0.13)(A_o,~D_o) = (-142^\circ.61 \pm 0^\circ.08, -63^\circ.58 \pm 0^\circ.13). Similarly, King 5 consists of 403 probable members with mean proper motion components (μαcosδ, μδ)=(0.291±0.005,1.256±0.005)(\mu_\alpha\cos\delta,~\mu_\delta) = (-0.291 \pm 0.005, -1.256 \pm 0.005) mas yr1^{-1} and a limiting radius of 11.332.16+5.4511.33_{-2.16}^{+5.45} arcminutes. The cluster's age is determined as 1.45±0.101.45 \pm 0.10 Gyr, with a distance of 2220±402220 \pm 40 pc and a metallicity of [Fe/H]=0.15\text{[Fe/H]} = -0.15 dex (z=0.0109z = 0.0109). We identify 4 centrally concentrated BSSs, and the total mass is estimated as 484±22 M484 \pm 22~M_{\odot}. The apex motion is calculated as (Ao, Do)=(115.10±0.09,73.16±0.12)(A_o,~D_o) = (-115^\circ.10 \pm 0^\circ.09, -73^\circ.16 \pm 0^\circ.12). The orbital analysis of King 2 and King 5 indicates nearly circular orbits, characterized by low eccentricities and minimal variation in their apogalactic and perigalactic distances. King 2 and King 5 reach maximum heights of 499±25499 \pm 25 pc and 177±2177 \pm 2 pc from the Galactic plane, respectively, confirming their classification as young stellar disc population.

Keywords

Cite

@article{arxiv.2503.07730,
  title  = {Study of Open Star Clusters Using the Gaia DR3: I- Poorly Studied King 2 and King 5},
  author = {Aly Haroon and Waleed Elsanhoury and Essam Elkholy and Abdel naby Saad and Deniz Cennet Çınar},
  journal= {arXiv preprint arXiv:2503.07730},
  year   = {2025}
}

Comments

27 pages, including 11 figures and 8 tables, accepted for publication in the Physica Scripta