Unveiling the binary nature of NGC 2323

作者：Songmei Qin, Jing Zhong, Tong Tang, Yueyue Jiang, Long Wang, Kai Wu, F. Anders, L. Balaguer-Núñez, Guimei Liu, Chunyan Li, Jinliang Hou, Li Chen · 发表于：Astronomy and Astrophysics · 年份：2025 · DOI：10.1051/0004-6361/202452962 · 被引用次数：7 · 研究领域：Stellar, planetary, and galactic studies、Astronomy and Astrophysical Research、Astro and Planetary Science

Context . As a well-known open cluster, NGC 2323 (also called M50) has been widely investigated for over a hundred years and has always been considered a classical single cluster. Aims . We studied the binary structure nature of NGC 2323 with Gaia Data Release 3 (DR3). Methods . We discovered the binary structure of NGC 2323 by the HDBSCAN algorithm based on the astrometric and photometric data from Gaia DR3. Then we employed the PETAR N -body code to investigate its binary structure origin. Results . We found that NGC 2323 consists of two distinct subclusters (NGC 2323-a and NGC 2323-b) that are still gravitationally bound. They have very close positions (three-dimensional Δpos = 12.3 pc, σ Δpos = 3.4 pc) and similar tangential velocities (two-dimensional ΔV = 2.2 km s −1 , σ ΔV = 0.02 km s −1 ). The best isochrone fitting ages of the two clusters are the same (158 Myr), further proving their possibly common origin. The numerical N -body simulation suggests that the less massive cluster is unlikely to be the cluster tidal tails created by the differential rotation of the Milky Way.