Unveiling hidden stellar aggregates in the Milky Way: 1656 new star clusters found in Gaia EDR3

TL;DR

This study used Gaia EDR3 data and an unsupervised machine learning algorithm to discover 1,656 new star clusters in the Milky Way, significantly expanding the catalog of known clusters and providing detailed parameters for further research.

Contribution

The paper introduces a novel data preparation method combined with DBSCAN to blindly identify star clusters, increasing the known population by over half in the Gaia era.

Findings

Identified 1,656 new star clusters beyond 1.2 kpc in the Galactic disk.

New clusters are generally older and located in regions with lower extinction.

Total new clusters detected with this method amount to 2,541, covering 55% of recent discoveries.

Abstract

We report 1,656 new star clusters found in the Galactic disk (|b|<20 degrees) beyond 1.2 kpc, using Gaia EDR3 data. Based on an unsupervised machine learning algorithm, DBSCAN, and followed our previous studies, we utilized a unique method to do the data preparation and obtained the clustering coefficients, which proved to be an effective way to search blindly for star clusters. We tabulated the physical parameters and member stars of the new clusters, and presented some interesting examples, including a globular cluster candidate. The cluster parameters and member stars are available at CDS via anonymous ftp to https://cdsarc.cds.unistra.fr/ftp/vizier.submit//he22c. We examined the new discoveries and discussed their statistical properties. The proper motion dispersions and radii of the new clusters were the same as the previously reported ones. The new star clusters beyond 1.2 kpc were older than those in the solar neighborhood, and the new objects found in the third Galactic quadrant presented the lowest line-of-sight extinctions. Combined with our previous results, the total population of new clusters detected through our method was 2,541, corresponding to 55% of all newly published clusters in the Gaia era. The number of cataloged Gaia star clusters was also increased to nearly six thousand. In the near future, it is necessary to make a unified confirmation and member star determination for all reported clusters.