Giant outbursts of clumpy material preceding Type II supernova 2024qiw

TL;DR

This paper presents evidence of giant, clumpy mass-loss outbursts from a massive star shortly before its core-collapse supernova, challenging existing stellar evolution models and revealing diverse pre-explosion phenomena.

Contribution

It provides observational evidence of eruptive mass loss akin to LBV eruptions occurring just before a supernova, which is a novel insight into late-stage stellar evolution.

Findings

Detected a bumpy light curve and variable polarization indicating interaction with clumpy circumstellar material.

Estimated a high mass-loss rate of over 10^{-2} solar masses per year.

Observed a Type II supernova despite high pre-explosion mass loss, indicating diverse mass-loss processes.

Abstract

Observations of core-collapse supernovae suggest that some massive stars undergo intense mass loss shortly before explosion, but the underlying mechanisms remain unknown. Here we report evidence of giant outbursts of clumpy material from a massive star in the final decades before explosion. Photometric, spectroscopic, and polarimetric data of SN~2024qiw reveal a bumpy light curve, a broad H$\alpha$ profile, and variable polarization, all consistent with interaction between SN ejecta and clumpy circumstellar material, implying a mass-loss rate of $\gtrsim 10^{-2}$ M$_\odot$ yr$^{-1}$. Taken together, the most likely explanation is multiple major eruptions, similar to those of Luminous Blue Variables (LBVs), but occurring shortly before explosion. This challenges standard stellar evolution theory by requiring either that LBVs explode terminally, or that other evolutionary phases produce eruptive episodes. In spite of very high pre-SN mass loss, the resulting SN is of Type~II, rather than Type IIn, highlighting diverse and previously unrecognized late-stage mass-loss processes.