Characterising the Kinematics and Evolution of Young Stellar Groups within 1 kpc of the Sun Using Gaia DR3

Abstract

Star-forming regions are key to understanding the formation and early evolution of stars. Young stellar objects (YSOs) form groups with distinct kinematic and spatial properties, inherited from the turbulent dynamics of their parent molecular clouds. The high-precision astrometry and photometry from Gaia Data Release 3 (DR3) enable detailed studies of these groups' three-dimensional motions and their evolutionary stability. This study aims to investigate the kinematic properties and evolutionary consistency of YSO associations in the solar neighbourhood. Here, we show that HDBSCAN clustering of Gaia DR3 data yields 145 YSO groups comprising 5713 stars within 1 kpc, with a derived Larson's relation of $σ_v = (1.10 \pm 0.13) \times r^{0.38 \pm 0.03}$, consistent across age bins up to 20 Myr. This slope aligns with the canonical value of 0.38 and typical ranges of 0.4--0.5. The stable Larson's relation across ages indicates that the inherited turbulent structure from parent clouds persists without significant disruption. These findings establish a benchmark for studying the kinematic legacy of star-forming regions.