Speaker
Description
Supernovae exhibiting circumstellar matter (CSM) interactions and dynamic signatures provide critical insights into the mass-loss histories of massive stars. SN2022ffg, a Type II supernova observed shortly after the explosion, displayed flash-ionized emission lines of H, He, N, and C lasting for over a week, indicating interaction with a dense nearby CSM. The supernova’s Swift-UV light curve peaked within 5 days, subsequently settling into a rare 20-day plateau, which has never been seen in Type II SNe, while its bolometric light curve remained notably steady over 30 days. Spectroscopic and polarimetric observations reveal a complex, asymmetric CSM structure surrounding the progenitor, with an inner dense CSM and outer shell-like CSM indicated by boxy line profiles during the photospheric phase. Light curve modeling across UV-optical-NIR wavelengths suggests a mass-loss rate of approximately 0.01 Msolar per year and an explosion energy exceeding 2 foe. These observations support the growing understanding that asphericity, often resulting from complex mass-loss processes in massive stars, is a common feature in their CSM environments rather than an exception.
