A pre-explosion effervescent zone for the circumstellar material in SN 2023ixf

TL;DR

This paper introduces the effervescent zone model to explain the dense, compact circumstellar material around SN 2023ixf, suggesting bound clumps lifted by stellar pulsation contribute significantly to the CSM without requiring recent outbursts.

Contribution

The paper proposes a novel effervescent zone model where bound clumps from stellar pulsation form the dense CSM, offering an alternative to high mass loss rate wind scenarios.

Findings

Dense clumps have >3000 times the wind density at the same radius.

Clumps occupy several percent of the volume near the progenitor.

Effervescent zone explains CSM without recent outbursts.

Abstract

I present the effervescent zone model to account for the compact dense circumstellar material (CSM) around the progenitor of the core collapse supernova (CCSN) SN 2023ixf. The effervescent zone is composed of bound dense clumps that are lifted by stellar pulsation and envelope convection to distances of tens AUs, and then fall back. The dense clumps provide most of the compact CSM mass and exist alongside the regular (escaping) wind. I crudely estimate that for a compact CSM within ~30 AU that contains ~0.01 Mo, the density of each clump is >3000 times the density of the regular wind at the same radius and that the total volume filling factor of the clumps is several percent. The clumps might cover only a small fraction of the CCSN photosphere in the first days post-explosion, accounting for the lack of strong narrow absorption lines. The long-lived effervescent zone is compatible with no evidence for outbursts in the years prior to SN 2023ixf explosion and the large-amplitude pulsations of its progenitor, and it is an alternative to the CSM scenario of several-years-long high mass loss rate wind.