Detached and continuous circumstellar matter in Type Ibc supernovae from mass eruption.

The article focuses on modeling the diverse structures of hydrogen-poor circumstellar matter (CSM) observed around interacting Type Ibc supernovae (SNe), which result from eruptive mass loss shortly before core-collapse. It demonstrates that partial eruptions of stripped stars produce both unbound CSM and a bound portion that falls back toward the star, with stellar feedback—via radiation pressure and winds—potentially pushing this fallback CSM outward to large radii (≳10¹⁵ cm) over several years, creating detached CSM shells. This interplay explains the observed variation in CSM interaction timing, such as early signatures in Type Ibn/Icn SNe and delayed signatures in recently discovered Type Ic SNe with detached CSM. The model is supported by radiation hydrodynamical simulations and analytical calculations, and it suggests that the timing and structure of CSM depend on factors like the progenitor’s luminosity, mass-loss rate, and the interval between eruption and core-collapse.