Fireworks from Massive Stars at the End of their Lives

Raffaella Margutti (NYU)

Observations are drawing a complex picture of the last stages of the evolution of massive stars and their explosions. In this seminar I concentrate on one among the least understood aspects of stellar evolution, adopting an observational perspective: How do massive stars lose a significant fraction of their mass in the years preceding the explosion? I address this question by taking advantage of panchromatic observations of two remarkable explosions: the puzzling, double explosion of SN2009ip in 2012, and the supernova chameleon SN2014C. SN2014C underwent a dramatic metamorphosis, evolving from a normal H-stripped SN of type Ib into a strongly interacting SN of type IIn, thus violating the Type I vs. Type II SN classification that has existed for decades.