Identifying Candidate Moving Groups in the Gaia Catalog

Abstract

Gaia is a European satellite mission recording positional and radial velocity measurements for about a billion stars in order to create a three-dimensional map of the Milky Way Galaxy. Stars form in groups within giant molecular clouds of gas and dust and are gravitationally bound in what is known as open clusters. The members of an individual cluster share similar kinematic properties as the cluster orbits the Galactic center. Over time open clusters dissolve due to the equipartition process, or disruption from tidal encounters; however the former members still share common motions despite being spread out across the Galaxy. Dismantled members from a given cluster are collectively known as a moving group. Using the Python programming language, we calculated the three-dimensional space velocity components and their uncertainties for individual stars in the Gaia catalog. Once these values were determined, we developed a method to search through the catalog and identify stars with common kinematic properties that have potential to constitute a moving group. We have compiled a list of 450 candidate moving groups with at least five members; 38 of the candidate groups contain ten or more members. These data will be used in future observing projects to look for other indications, such as common metallicities, to confirm the possible members are related.