2025/04/16 by Bore Gao, Gao, Bore Annie, Catherine Zucker +32
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Stellar, planetary, and galactic studies
paper · doi:10.48550/arxiv.2504.12381
openalex publication_date 2025/04/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The IRAS Vela Shell (IVS) is a structure of enhanced FIR emission located towards the Gum Nebula, a prominent region of \rm Hα emission in the local Milky Way shaped by various galactic stellar feedback over the past several million years. We constrain the 3D spatial geometry of the IVS using a parsec-resolution 3D dust map and contextualize it within the broader Gum Nebula. Our analysis reveals a dense, bowl-like IVS structure below the Galactic plane, with a more diffuse component above. We obtain a total shell mass of 5.1-2.4+2.4× 104 \rm M\odot and, incorporating previous studies on shell expansion, a momentum of 6.0-3.4+4.7× 105 \rm M\odot km s-1. We find a spatial correlation between the morphology of the dust-traced IVS and the Gum Nebula's \rm Hα emission when projected onto the sky. We quantify contributions of feedback from stellar winds, an expanding HII region, and supernovae to the IVS formation, finding that stellar winds are subdominant. Our momentum analysis shows that both an HII region and supernova feedback could drive the shell's expansion. Using astrometric constraints from Gaia and Hipparcos, we trace back nearby feedback sources and find that the massive stars γ2 Velorum and ζ Puppis are currently within the IVS, producing enough ionizing luminosity to form an HII region of comparable size. Alternatively, if the IVS' momentum is primarily driven by supernovae, 1-2 events would be required. We also identify several young massive clusters that could have hosted supernovae within the past 3 Myr.