VizieR Online Data Catalog: Stars groups in CMa OB 1 with Gaia DR2 (Santos-Silva+, 2021)
Abstract
Aiming at clarifying the complex star-forming history of CMa OB1 and confirming its cluster membership, we conduct a multidimensional study of stellar groups in the region, taking into account the positions, proper motions, and parallax from the Gaia DR2 catalogue (Gaia Collaboration et al. 2018A&A...616A...1G, Cat. I/345).
This stars catalogue allows us to apply a list of criteria selections within a search radius of 4.1 degrees centred on the coordinates covering the entire CMa OB1 association. (i.e section 2.1 Sample selection). After applying all of these criteria, our final sample contains 249522 stars. Hereafter, we proceed to a substructure search (see section 3). Clustering methods constitute the most commonly used technique of unsupervised learning and are a powerful tool for data analysis. There are several clustering algorithms, but one shown to be powerful and efficient in different astronomy fields is Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN), which has been used to search for stellar clusters (Castro-Ginard et al. 2020A&A...635A..45C, Cat. J/A+A/635/A45). Thus, we use this algorithm in the 5D space of astrometric parameters (pmRA, pmDE, Plx, RAdeg, DEdeg) which giving birth to 29 stellars groups. To validate the clusters identified by HDBSCAN and estimate the membership probability of each star belonging to a specific group, we have computed 400 bootstrap repetitions, taking into account the uncertainties of the astrometric parameters of the stars. We attribute a membership probability P of each star belonging to a specific cluster according to the percentage of assignment to it. We considered that a star is a cluster member if it is assigned to a specific cluster in at least 50 per cent of the realizations (P>=50 per cent). Results are available in the table cma00.dat to cma28.dat. This method is similar to that one described by Limberg et al. (2021ApJ...907...10L, Cat. J/ApJ/907/10), (i.e please refer to sections 3.1 Searching for groups and 3.2 Validation). More, we further apply a second memebership validation test (explained in the section 3.2.2 Bayesian method) on our results based on comparison with a recent study of the young population related to our groups. (29 data files).- Publication:
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VizieR Online Data Catalog
- Pub Date:
- July 2024
- Bibcode:
- 2024yCat..75081033S
- Keywords:
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- Milky Way;
- Associations: stellar;
- Star Forming Region;
- Astrometric data;
- Stars: distances;
- Optical;
- Extinction;
- Space velocities