AI 中文总结
利用高精度盖亚DR3等数据，对疏散星团NGC 2266和NGC 2324进行分析，用无监督机器学习技术识别成员，通过多种方法得出星团距离、半径、年龄等参数，揭示其动力学结构，凸显盖亚天体测量在星团研究中的作用。
AI 中文摘要
我们使用高精度盖亚DR3数据，并辅以2MASS和LAMOST DR7目录，对研究充分的中等年龄疏散星团NGC 2266和NGC 2324进行了精确的天体测量和光度分析。利用无监督机器学习技术识别可能的星团成员，应用高斯混合模型（GMM）和\texttt{pyUPMASK}。发现基于GMM的成员样本在盖亚星等-颜色图中产生的星团序列比\texttt{pyUPMASK}更清晰、更连贯。确定了NGC 2266和NGC 2324分别有719个和852个高概率成员（$P \geq 0.7$）。通过视差法测定NGC 2266的距离为3.55 $\pm$ 0.23 kpc，NGC 2324的距离为4.18 $\pm$ 0.24 kpc。两个星团的半径估计分别为7.23 $\pm$ 0.47 pc和10.94 $\pm$ 0.63 pc。等时线拟合估计NGC 2266的年龄为$1.1 \pm 0.1$ Gyr，NGC 2324的年龄为$790 \pm 150$ Myr。这些年龄估计分别假设金属丰度为$Z = 0.0084$和$Z = 0.0038$。金氏轮廓拟合表明两个星团都呈现出紧凑、明确的径向结构。它们的潮汐半径分别为NGC 2266的$8.84'$（9.13 pc）和NGC 2324的$10.97'$（13.34 pc）。当前质量函数的斜率对于NGC 2266为$1.13\pm0.18$，对于NGC 2324为$1.24\pm0.19$，表明低质量恒星不足。导出的质量函数斜率与两个星团的动力学演化一致。星团显示出短的弛豫时间，而只有NGC 2324有轻微的质量分层迹象。这项研究突出了盖亚天体测量在解析疏散星团内部结构和完善其动力学参数方面的能力。
英文摘要
We present a refined astrometric and photometric analysis of the well-studied intermediate-age open clusters NGC 2266 and NGC 2324 using high-precision Gaia DR3 data, complemented by 2MASS and LAMOST DR7 catalogs. Probable cluster members are identified using unsupervised machine learning techniques. We apply both Gaussian Mixture Models (GMMs) and \texttt{pyUPMASK}. We find that the GMM-based membership sample yields a cleaner, more coherent cluster sequence in the Gaia CMDs than pyUPMASK. We identified 719 and 852 high-probability members ($P \geq 0.7$) for NGC 2266 and NGC 2324, respectively. Using the parallax method, we determine distances of 3.55 $\pm$ 0.23~kpc for NGC 2266 and 4.18 $\pm$ 0.24~kpc for NGC 2324. The radius estimates for both clusters are 7.23 $\pm$ 0.47 pc and 10.94 $\pm$ 0.63 pc. Isochrone fitting estimated ages of $1.1 \pm 0.1$~Gyr for NGC 2266 and $790 \pm 150$~Myr for NGC 2324. These age estimates were derived assuming metallicities of $Z = 0.0084$ and $Z = 0.0038$, respectively. The King profile fitting indicates that both clusters exhibit compact, well-defined radial structures. Their tidal radii are $8.84'$ (9.13 pc) for NGC 2266 and $10.97'$ (13.34 pc) for NGC 2324. The slopes of the present-day mass functions are $1.13\pm0.18$ for NGC 2266 and $1.24\pm0.19$ for NGC 2324, indicating a deficiency of low-mass stars. The derived mass-function slopes are consistent with dynamical evolution in both clusters. The clusters exhibit short relaxation times, while only NGC 2324 shows a mild indication of mass segregation. This study highlights the power of Gaia astrometry to resolve internal structures within open clusters and refine their dynamical parameters.
Comments22 pages, 16 figures, 5 tables, accepted for publication in Advances in Space Research
