A large, long-lived, slowly-expanding superbubble across the Perseus arm

Stellar feedback is a crucial mechanism in galactic evolution, as demonstrated by the widespread bubbles observed with JWST. In this study, we combine data from Gaia and LAMOST to obtain a sample of young O-B2 stars with full three-dimensional velocity information. Focusing on the largest known superbubble in the Milky Way, we identify groups of O-B2 stars at its periphery, exhibiting a transverse velocity of 25.8 km s−1 and an expansion velocity of 6.2 km s−1. Using these velocities, we calculate a crossing time tcross ≈ 20 Myr and an expansion timescale texpansion ≈ 80 Myr. We estimate a survival timescale tsurvival ≈ 250 Myr and a supernova interval tSN≈0.1 Myr. Together with the Galactic shear timescale tshear ≈ 30 Myr, these values satisfy tSN