Light curves of electron capture and Fe core collapse supernovae: The diagnostic method of electron capture supernovae
Speaker: Masato Sato
Abstract:
While massive stars (M>~10Msun) explode as Fe core collapse supernovae (FeCCSNe) at their last moment, those have slightly lower mass (M~8-10Msun) are theoretically expected to form O+Ne+Mg degenerated core, become Super Asymptotic Giant Branches (SAGB) and finally explode as electron capture supernovae (ECSNe) if their envelope is remained (Miyaji et al. 1980; Nomoto et al. 1982; Nomoto 1984, 1987). However, such evolutionary path and the mass boundary between FeCCSN and ECSN are not confirmed and constrained by observation because of insufficient observations of ECSNe. The reasons why we could hardly diagnose ECSN clearly are that observational characteristics of ECSNe comparing to low-mass FeCCSNe are not understood sufficiently, and the diagnostic method of ECSNe is not established yet. Although Kozyreva et al. (2021) shows that ECSN has blue plateau, they don’t include circumstellar material (CSM) interaction. However, CSM interaction might change the light curve significantly (Moriya et al. 2018). Thus, we synthesized the multicolor light curves of ECSNe and low-mass FeCCSNe including CSM interaction using the multi-group radiation hydrodynamics code, STELLA (Blinnikov et al. 1993). As a result, ECSN is revealed to show bluer plateau than low-mass FeCCSN even if it has reasonably dense CSM. Using this characteristic, we propose the first diagnostic method of ECSN in which the transition time from plateau to tail phase (tPT) and the color index B-V at tPT/2 are used. In the talk, we will show the calculated light curves of ECSN and low-mass FeCCSN and discuss their characteristics. In addition, we will propose the diagnostic method of ECSN. Also, we will mention our future work in which we will try to find an ECSN and reveal its nature.