Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue

TL;DR

This paper presents a new automated method to determine proper motions and membership probabilities for open clusters using the Bordeaux PM2000 catalogue, including first proper motion data for five clusters.

Contribution

It introduces a novel automated approach combining parametrisations and genetic algorithms for cluster membership analysis, applied to 49 clusters in the Bordeaux PM2000 catalogue.

Findings

First proper motions for five open clusters.

Confirmed non-existence of two suspected clusters.

Provided a comprehensive catalogue of kinematic parameters.

Abstract

We derive lists of proper-motions and kinematic membership probabilities for 49 open clusters and possible open clusters in the zone of the Bordeaux PM2000 proper motion catalogue ($+11^{\circ}\le\delta\le+18^{\circ}$). We test different parametrisations of the proper motion and position distribution functions and select the most successful one. In the light of those results, we analyse some objects individually. The segregation between cluster and field member stars, and the assignment of membership probabilities, is accomplished by applying a new and fully automated method based on both parametrisations of the proper motion and position distribution functions, and genetic algorithm optimization heuristics associated with a derivative-based hill climbing algorithm for the likelihood optimization. We present a catalogue comprising kinematic parameters and associated membership probability lists for 49 open clusters and possible open clusters in the Bordeaux PM2000 catalogue region. We note that this is the first determination of proper motions for five open clusters. We confirm the non-existence of two kinematic populations in the region of 15 previously suspected non-existent objects.