CALTECH CORE-COLLAPSE PROJECT (CCCP) OBSERVATIONS OF TYPE II SUPERNOVAE: EVIDENCE FOR THREE DISTINCT PHOTOMETRIC SUBTYPES

Abstract

We present R-Band light curves of Type II supernovae (SNe) from the Caltech\nCore Collapse Project (CCCP). With the exception of interacting (Type IIn) SNe\nand rare events with long rise times, we find that most light curve shapes\nbelong to one of three distinct classes: plateau, slowly declining and rapidly\ndeclining events. The last class is composed solely of Type IIb SNe which\npresent similar light curve shapes to those of SNe Ib, suggesting, perhaps,\nsimilar progenitor channels. We do not find any intermediate light curves,\nimplying that these subclasses are unlikely to reflect variance of continuous\nparameters, but rather might result from physically distinct progenitor\nsystems, strengthening the suggestion of a binary origin for at least some\nstripped SNe. We find a large plateau luminosity range for SNe IIP, while the\nplateau lengths seem rather uniform at approximately 100 days. As analysis of\nadditional CCCP data goes on and larger samples are collected, demographic\nstudies of core collapse SNe will likely continue to provide new constraints on\nprogenitor scenarios.\n