Time evolution of nuclear burning luminosity excluding neutrino emission for each model. Details about each model are given in Sect. 2.1. A more massive star has a shorter timescale of burning, and therefore each burning stage starts at the moment closer to the time of core collapse. In this figure, RSG1 and RSG2 experience a sudden increase of nuclear burning luminosity because of the beginning of the core neon burning at about ten and 0.8 yr before core collapse, respectively. On the other hand, for model YSG, central carbon burning still continues at 0.1 yr before core collapse.