Towards a census of the Galactic anticentre star clusters II: exploring lower overdensities

TL;DR

This study investigates 48 stellar overdensities towards the Galactic anticentre, identifying 18 star clusters, including 7 new discoveries, and deriving their fundamental parameters to improve the open cluster census in that region.

Contribution

The paper provides the first detailed analysis of low-level overdensities in the Galactic anticentre, discovering new clusters and refining the parameters of known ones using advanced photometric techniques.

Findings

Identified 18 star clusters from 48 overdensities.

Discovered 7 new star clusters, mostly associated with nebulae and OB associations.

Confirmed the location of several clusters within the Perseus arm.

Abstract

We investigate the nature of 48 low-level stellar overdensities (from Froebrich, Scholz, and Raftery catalogue - FSR07) projected towards the Galactic anticentre and derive fundamental parameters for the confirmed clusters, thus improving the open cluster (OC) census in that direction. Parameters are derived with field-star decontaminated photometry, colour-magnitude filters and stellar radial density profiles. Among the 48 targets, we identified 18 star clusters, 6 previously studied OCs, and 7 probable clusters that require deeper photometry to establish the nature. We discovered 7 new clusters, 6 of them forming an association of clusters with BPI 14, FSR 777, Kronberger 1, and Stock 8 in the region of the nebula IC 417 and related to the Aur OB2 association, and one embedded in the nebula Sh2-229. We also derive parameters for these three non-FSR07 clusters, because they are important in determining the structure of the Galactic anticentre. Thus, 58 objects are analysed in this work and we could derive fundamental parameters for 28 of them. The scenario in the IC 417 star forming region is consistent with a sequential event. FSR 888 and FSR 890 are embedded in Sh2-249 within the Gem OB1 association. According to the distance derived for these clusters and those in the association of clusters, both Aur OB2 and Gem OB1 are located in the Perseus arm.