Exploring the Structure and Evolution of Four Young Open Clusters Near the Galactic Mid-plane via Gaia DR3

TL;DR

This study uses Gaia DR3 data to analyze four young open clusters near the Galactic plane, determining their membership, ages, masses, dynamics, and orbits, revealing their properties and evolutionary states.

Contribution

It provides a comprehensive multi-faceted analysis of four young open clusters using Gaia DR3, including membership, ages, mass functions, dynamics, and orbital characteristics, which is novel.

Findings

Cluster ages range from 10 to 140 million years.

Mass function slopes are consistent with the Salpeter IMF.

Only two clusters are dynamically relaxed.

Abstract

We present a comprehensive analysis of four young open clusters, NGC 663, NGC 2301, NGC 2384, and NGC 7510, utilizing high-precision astrometric and photometric data from Gaia DR3. Cluster membership was determined using the UPMASK algorithm, resulting in probable member counts ranging from 337 to 1498 across the clusters. Bayesian MCMC isochrone fitting yielded cluster ages in the range $\log t \sim 7.0$ -$8.15$, with uncertainties of $\sim 0.11$-$0.18$. Reddening values ranged from $E(B-V)=0.093$ mag in NGC 2301 to $1.24$ mag in NGC 7510, consistent with their positions near the Galactic plane. The stellar mass function slopes ($\alpha \approx 2.00$-$2.26$) closely match the Salpeter IMF, with total stellar masses spanning nearly an order of magnitude, from $\sim 486\,M_\odot$ in NGC 2301 to $\sim 3584\,M_\odot$ in NGC 663. Dynamical relaxation times indicate that only NGC 2301 ($\tau \approx 10.00$) and NGC 2384b ($\tau \approx 2.03$) are dynamically relaxed; the others remain dynamically evolving. Orbital integrations in the MWPotential2014 model reveal nearly circular Galactic orbits with very low eccentricities ($e \approx 0.003$-$0.014$) and small vertical distances ($Z_{\rm max} < 0.142$ kpc), confirming their confinement to the thin disk. SED and kinematic analysis show that NGC 2384a and NGC 2384b are separated by $\sim 0.55$ kpc, indicating an optical pair.