Light curves of electron capture and low mass Fe core collapse supernovae

speaker: Masato Sato

Stars with M<8Msun become white dwarfs in their last moment. Stars with M>10Msun evolve to Red Super Giant (RSG) or Wolf-Rayet and explode as Fe core collapse supernovae (FeCCSNe). The last moment of the M~8-10Msun is a one of the last unknown pieces of stellar evolution understanding. They make O, Ne, and Mg core at their center in the later phase of evolution. They are theoretically predicted to evolve to Super Asymptotic Giant Branch (SAGB) and finally become white dwarfs or explode as electron capture supernovae (ECSNe). However, mass range to become SAGB is not accurately estimated. Moreover, there are no supernovae which clearly identified as electron capture origin so far. SN2018zd were observed and proposed as an ECSN recently (Hiramatsu et al. 2021). However, it is also proposed as a FeCCSN (Callis et al. 2022) and common understanding is not obtained so far. Therefore, the clear identification of ECSN-like supernovae like SN2018zd is highly required. Although Kozyreva et al. (2021) revealed the bluer plateau for ECSN than FeCCSN, they didn’t include circumstellar material (CSM) interaction. However, recent observations and studies revealed that most of the supernovae have CSM before explosion. Therefore, the realistic characteristics of the ECSN light curves and the distinguishing method of it aren’t revealed.
We conducted numerical calculation of the light curves of low-mass FeCCSN and ECSN using multi-dimensional radiation hydrodynamical code STELLA (Blinnikov et al. 2000). RSG and SAGB progenitor models are taken from Sukhbold et al. (2016) and Tominaga et al. (2013) respectively. We include the CSM interaction into calculation using the method of Moriya et al. (2018).
We investigated the characteristics of the ECSN light curves comparing to low-mass FeCCSN. As a result, the bluer plateau for ECSN than FeCCSN is confirmed if CSM is not included and even if they are bolometrically degenerated. Moreover, as a preliminary result, the redder and fainter delayed shockbreakout is shown for ECSN than FeCCSN if CSM with high mass loss rate(~1e-2Msun/yr) is included. With low mass loss rate(~1e-4-6Msun/yr), bluer plateau for ECSN still can be seen. In the talk, we will introduce the progenitor models and resulting light curves in the talk.