Description
Late-time shock interaction between supernova (SN) ejecta and circumstellar material (CSM) offers a powerful probe of the mass-loss history of massive stars and the dynamics of stellar explosions. This interaction is critical for understanding the final stages of stellar evolution and the diversity of core-collapse supernovae (CCSNe). While shock interaction signatures have been observed in a range of CCSNe, they vary significantly depending on the progenitor’s mass-loss history, the structure of the CSM, and the explosion dynamics.
With a given opportunity, in the talk, I will explore late-time shock interaction as a key mechanism influencing the evolution of Type II SNe, focusing on the broader implications for the entire class. As a striking example, I will discuss SN 2023ixf, a nearby Type II SN in M101, whose late-time spectra exhibit prominent signatures of ejecta-CSM interaction (Kumar et al. 2025, MNRAS, 538, 659K). Observations taken nearly a year post-explosion reveal unique Halpha features and asymmetries that shed light on episodic mass loss occurring nearly 300-1000 years before core collapse. This detailed case study provides insight into the mechanisms driving shock interaction and highlights the role of progenitor mass loss in shaping supernova evolution.
By comparing SN 2023ixf with other interacting supernovae, I will demonstrate how late-time spectroscopy can uncover the diversity in pre-supernova mass loss and explosion dynamics. This study underscores the importance of systematic late-time observations in advancing our understanding of massive star death and the environments they shape.
