Early Warning Signs: Precursor activity preceding supernovae

Over the last two decades, several instances of precursor activity have been observed just before a massive star goes supernova. One of the most famous cases is SN 2009ip, which exhibited erratic changes in brightness for three years before undergoing a supernova-like explosion in 2012. Thanks in part to all-sky photometric surveys, more instances of precursor activity in supernovae are now being detected, and with the first light of LSST, this pre-supernova activity is likely to become a common observation, potentially signaling an upcoming terminal explosion. While most of these precursor events belong to Type IIn supernovae, activity is being observed across various supernova subtypes. In this talk, I will provide an overview of the various types of precursor events that have been observed, including recently discovered instances in Type Ibn supernovae, which exhibit unusual precursor activity. Additionally, I will explore potential scenarios for the progenitors of these events, with a particular focus on interacting binary star systems and the detectable signatures of binarity prior to the supernova explosion. Finally, I will present the upcoming challenges in pre-SN detections during the Rubin era, highlighting the potential ability to identify future supernova explosions based on their precursor activities, ultimately improving our understanding of the final moments of massive star evolution.