AI 中文总结
本研究利用盖亚DR3和VVVX数据构建了疏散星团NGC 2437的最深近红外色星等图，精确测定其物理参数，为相关天体研究提供了更优条件。
AI 中文摘要
对银河系星团的深场测光为确定其物理性质提供了最强大的工具之一，尤其是在受严重消光和拥挤影响的低银纬区域。NGC 2437是VVV扩展巡天（VVVX）近红外覆盖范围内延伸最广的星团，在天球上覆盖超过1度。我们旨在利用盖亚DR3的光学数据和VVVX的近红外数据表征其物理性质，使用盖亚DR3的自行选择NGC 2437成员，以构建光学和近红外色星等图及色-色图。我们进一步利用新构建的VVVX深场叠合图像，获取了该星团目前可用的最深近红外色星等图。我们估算了NGC 2437的主要物理参数，包括平均视差为0.608毫角秒，自行（PMs）为（-3.85，0.41）毫角秒/年；星团天区的平均红化E(J-Ks)=0.059星等，消光A_k=0.034星等，无显著的微分红化弥散；估算出距离模数为11.08星等，对应距离为1644秒差距，这使NGC 2437位于银道面上方115秒差距处，银心距为9.24千秒差距。我们测量了星团的结构参数，得到核心半径为10.79角分；估算的总绝对星等为Mk=-4.91星等、Mv=-3.70星等；采用PARSEC-COLIBRI等时线（太阳金属丰度）测得星团平均年龄为3.5亿年，双星占比为28.6%。我们还讨论了修正后的星团参数对邻近疏散星团NGC 2425、行星状星云NGC 2438以及演化的OH/IR源OH231.8+04.2的影响。VVVX深场叠合将Ks波段测光深度提升了1.6星等，检测到的点源数量几乎翻倍，为整个南银道面恒星族群的研究提供了显著改善的条件。
英文摘要
Deep photometry of Galactic star clusters provides one of the most powerful tools for determining their physical properties. In particular, in low Galactic latitude regions that suffer from heavy extinction and crowding. NGC2437 is the most extended star cluster in the near-IR footprint of the VVV Extended Survey (VVVX), covering more than one degree on the sky. We aim to characterize its physical properties using Gaia DR3 in the optical and the VVVX in the near-IR. We use Gaia DR3 proper motions to select NGC2437 members in order to make optical and near-IR color-magnitude and color-color diagrams. We further exploited the newly constructed VVVX deep stack images to obtain the deepest near-IR color-magnitude diagram currently available for this cluster. We estimate the main physical parameters for NGC2437, including the mean parallax of 0.608 mas and PMs (-3.85, 0.41) mas/yr. The mean reddening E(J-Ks) = 0.059 mag and extinction of A_k = 0.034 mag for the cluster field, with no significant differential reddening spread. A distance modulus of 11.08 mag is estimated, equivalent to a distance of 1644 pc. This places NGC2437 at z=115 pc above the Galactic plane and at a galactocentric distance of 9.24 kpc. We measure the cluster structural parameters, obtaining a core radius of 10.79 arcmin. The estimated total absolute magnitudes are Mk = -4.91 mag and Mv = -3.70 mag. The cluster mean age is 350 Myr, using PARSEC-COLIBRI isochrones for solar metallicity. We measure a binary fraction of 28.6%. We also discuss the implications of the revised cluster parameters for the nearby open cluster NGC2425, the planetary nebula NGC2438, and the evolved OH/IR source OH231.8+04.2. The VVVX deep stacks increase the Ks photometric depth by 1.6 mag, nearly doubling the detected point sources and enabling significantly improved studies of stellar populations throughout the southern Galactic plane.
Comments9 pages, 12 figures, 1 tables. Accepted for Publication in A&A
