Description
Interacting transients provide invaluable insights into the final moments of the lives of massive stars, unveiling the mechanisms of pre-explosion mass loss, and tracing the amount, composition, and geometry of the CSM resulting from these processes.
I will present the transitional IIn SN 2024cld, discovered and classified just 12h post-explosion through the GOTO-FAST survey, and intensively followed for 200d after explosion. SN 2024cld shows marked similarities to SN 1998S and PTF11iqb: with strong flash-ionisation signatures close to explosion transitioning to persistent, narrow H emission all the way to +200d. High-resolution spectroscopy shows a sharp change in the structure of Halpha around +30d, providing evidence for two distinct CSM components, one we attribute to strong eruptive mass loss or binary shedding, and one tied to wind-driven mass loss.
Comprehensive imaging polarimetry also suggests changes in the asphericity of the photosphere as the ejecta sweeps the inner disk-like CSM, pointing towards further complexity in the mass loss prior to this. SN2024cld further underscores the chaotic and messy ends of red supergiant stars, driven by multiple mass loss mechanisms.
