Core-collapse supernovae are generally observed after the massive star has been destroyed, with information about the progenitor star inferred indirectly from the appearance and evolution of the supernova. Over the last decade, researchers have identified energetic activity at the locations of supernova explosions in the years leading up to core collapse in historical archives. These events are typically attributed to the massive progenitor star undergoing some form of activity via currently unknown mechanisms.
One challenge when observing these precursor events is the uncertainty surrounding when or if the actual supernova explosion will occur. This uncertainty often makes us hesitant to allocate valuable telescope time.
In this talk, I will present a growing sample of objects that demonstrate that some massive stars exhibit variability weeks to months before their final supernova. Through this work, we may be able to obtain advance warning of an impending supernova, allowing for high-reward observations and, to some extent, the ability to predict the final death of a massive star.