New star clusters discovered towards the Galactic anticentre direction using Gaia DR3 data

Abstract

We report the discovery of 31 new open clusters (OCs) identified in \textit{Gaia}~DR3 data through a systematic search over 220 adjacent $1^\circ\times1^\circ$ fields towards the Galactic anticentre, in the direction of the Perseus arm gap. Eight of them display low-density structures, possibly indicating open cluster remnants properties. The objects were identified and characterized through a combined analysis of photometric, kinematic, and spatial distributions, a methodology successfully applied in our previous works. Their structural properties, mean proper motions, ages, distances and reddening were derived and their centres cross-matched with the available catalogues. The clusters are low-concentrated systems and are mostly located within $3<d<5$ kpc, exhibiting reddening up to $E(B-V)\approx1.5$, and ages from $\sim$20 Myr to 1 Gyr. The new OCs represent a significant increase in the anticentre cluster census: $31\%$ for $3<d<4$ kpc and $12\%$ for $d>4$ kpc. They do not belong to the Perseus arm, but may be associated with the Outer Norma arm. The Gulf of Camelopardalis region appears as an interruption in the Perseus arm, possibly reflecting low star-formation activity, dust obscuration, or that the Milky Way is a flocculent, rather than a grand-design spiral galaxy.