May 15 – 17, 2026
College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)
Asia/Taipei timezone

Contesting between ML-MOC and HDBSCAN for Star Cluster Membership: A Case Study of M67 and M39

Not scheduled
15m
College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)

College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)

No. 1, Sec. 1, Liujia 5th Rd., Zhubei City, Hsinchu County 302, Taiwan 30272新竹縣竹北市六家五路一段1號
Board: 7

Speaker

Xin Tian (National Central University)

Description

We report the comparison of two machine learning clustering algorithms, ML-MOC and HDBSCAN, for determining star cluster membership. ML-MOC employs a combination of the k-Nearest Neighbors (k-NN) algorithm to find candidate members, followed by a Gaussian Mixture Model (GMM) for precise membership probability assignment. This makes it well-suited for regular, centrally concentrated clusters. In contrast, HDBSCAN is a density-based cluster-finding algorithm with a hierarchical structure, making it ideal for identifying extended features of arbitrary shapes. Using proper motion and parallax measurements from Gaia Data Release 3 (DR3), we applied these algorithms to two morphologically distinct targets: M67, a compact, well-defined open cluster, and M39, a cluster exhibiting extended tidal structures. Here we quantified the pros and cons of how each algorithm performed to uncover different clustering structures, e.g., in terms of completeness and reliability against field contamination, and how a combination of the two improves the membership determination.

Participate the oral/poster presentation award competition Yes

Author

Xin Tian (National Central University)

Co-author

Prof. Wen-Ping Chen (National Central University)

Presentation materials

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