Discovery of 178 Open Clusters with Gaia DR3

Abstract We present 178 new open cluster candidates identified through the application of the HDBSCAN clustering algorithm to astrometric data from the Gaia DR3 catalog. The analysis was performed over 5770 1 deg 2 fields centered on OB stars, which serve as tracers of Galactic spiral arms. Using the membership probabilities provided by HDBSCAN, we derived the mean proper motions, parallaxes, and fundamental parameters for each cluster. For a subset of 84 clusters, mean radial velocities were also determined using Gaia data. The cluster parameters (distances, ages, extinctions, and metallicities) were estimated through our nonsubjective multidimensional global optimization code, which fits theoretical isochrones to Gaia photometric data. The quality of the results and their uncertainty support the reality of the clusters, which span distances from 739 to 12,000 pc. Age estimates indicate that 59 clusters are younger than 50 Myr, 20 have intermediate ages, and 99 are classified as old clusters. These results highlight that there is still work to be done on open cluster discovery and reinforce the importance of regular updates to open cluster catalogs.