发表机构
National Research Institute of Astronomy and Geophysics (NRIAG); Akdeniz University, Faculty of Science, Department of Space Sciences and Technologies; Istanbul University, Institute of Graduate Studies in Science, Programme of Astronomy and Space Sciences（国家天文与地球物理研究所; 安塔利亚大学理学院空间科学与技术系; 伊斯坦布尔大学科学研究生院天文学与空间科学项目）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用Gaia DR3与2MASS数据，通过HDBSCAN算法识别NGC 7419疏散星团成员，经测光分析确定其基本参数，发现其恒星质量分布含三个不同质量种群，为该星团研究提供新视角。
AI 中文摘要
我们利用Gaia DR3和2MASS数据，对富含红超巨星与Be星的年轻疏散星团NGC 7419开展了结构、运动学及测光分析。采用HDBSCAN算法与保守的成员星判定标准，我们识别出734个高概率星团成员，将该星团与致密的英仙臂背景分离开来。对Gaia DR3色-星等图进行等时线拟合时，我们将经典Be星单独处理以考虑其星周 excess，得到年龄为15±2 Myr、距离为3161±261 pc、距离模数为12.50±0.08 mag，以及色余E(GBP-GRP)=2.58±0.06 mag。独立的2MASS分析给出一致的距离模数12.53 mag和E(J-Ks)=0.99 mag。Be星在J-Ks波段呈现显著的红外 excess，与星周盘的自由-自由及束缚-自由辐射一致。我们测得平均自行分别为-2.738±0.115 mas yr⁻¹和-1.604±0.149 mas yr⁻¹，平均视差为0.288±0.062 mas，对应三角视差距离为3316±317 pc，最终采用测光距离作为主要估计值。广义King轮廓给出核心半径为1.53±0.08 arcmin，极限半径为8.16±1.1 arcmin。恒星质量分布最适合用三组分高斯模型描述，我们将其解释为三个不同的质量种群，它们的共存与不完全混合符合NGC 7419的年轻动力学状态，层级形成机制为其起源提供了合理框架。
英文摘要
We present a structural, kinematic, and photometric analysis of the young, red supergiant- and Be star-rich open cluster NGC 7419 using Gaia DR3 and 2MASS data. Using the HDBSCAN algorithm and conservative membership criteria, we identify 734 high-probability cluster members, separating the cluster from the dense Perseus Arm background. Isochrone fitting to the Gaia DR3 color-magnitude diagram, treating classical Be stars separately to account for their circumstellar excess, yields an age of 15 +/- 2 Myr, a distance of 3161 +/- 261 pc, a distance modulus of 12.50 +/- 0.08 mag, and a color excess E(GBP-GRP) = 2.58 +/- 0.06 mag. An independent 2MASS analysis gives a consistent distance modulus of 12.53 mag and E(J-Ks) = 0.99 mag. The Be stars show a prominent infrared excess in J-Ks, consistent with free-free and bound-free emission from circumstellar disks. We derive mean proper motions of -2.738 +/- 0.115 and -1.604 +/- 0.149 mas yr^-1 and a mean parallax of 0.288 +/- 0.062 mas, corresponding to a trigonometric distance of 3316 +/- 317 pc. The photometric distance is adopted as the primary estimate. A generalized King profile gives a core radius of 1.53 +/- 0.08 arcmin and a limiting radius of 8.16 +/- 1.1 arcmin. The stellar mass distribution is best described by a three-component Gaussian model, which we interpret as three distinct mass populations. Their coexistence and incomplete mixing are consistent with the young dynamical state of NGC 7419. Hierarchical formation provides a plausible framework for their origin.
Comments20 pages, 17 figures, 14 tables. Accepted for publication in Research in Astronomy and Astrophysics (RAA)
