Work

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

Year: 2025

Type: article

Abstract: 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 $${t}_{{{\rm{SN}}}}\approx 0.1$$ Myr. Together with the Galactic shear timescale tshear ≈ 30 Myr, these values satisfy $${t}_{{{\rm{SN}}}} < {t}_{{{\rm{shear}}}} < {t}_{{{\rm{survival}}}}$$ . The energy and momentum from supernovae are sufficient to sustain the bubble’s growth against ambient pressure. This indicates that repeated supernovae replenish energy faster than shear and turbulent distort the cavity. Our analysis classifies the Giant Oval Cavity as a large, quasi-stationary superbubble, similar to the Phantom Bubble observed by JWST, stabilised by the interplay between stellar feedback and Galactic disk dynamics. This study identifies the Giant Oval Cavity as a large, long-lived superbubble in the Perseus Arm. Its slow expansion, sustained by frequent supernovae, balances Galactic shear and turbulent pressure, revealing a quasi-stationary feedback structure crucial for galactic evolution.

Source: Nature Communications

DOI: 10.1038/s41467-025-65591-5