Astrophysics with Radioactive Isotopes

'Ni problem' in Canonical and Ultrastripped Supernova Explosions

Not scheduled

20m

Oral Presentation

Speaker

Ryo Sawada (The University of Tokyo)

Description

Details of the explosion mechanism of core-collapse supernovae (CCSNe) are not yet fully understood. There is now an increasing number of successful examples of reproducing explosions in the first-principles simulations, which have shown a slow increase of explosion energy. However, it was recently pointed out that the growth rates of the explosion energy of these simulations are insufficient to produce enough $^{56}$Ni mass to account for observations. We refer to this issue as the "nickel mass problem" (Ni problem, hereafter; Sawada et al. 2019, Suwa et al. 2019, Sawada & Suwa 2021).
Also similar to this issue, the apparent 56Ni problem in Ultrastripped supernovae (USSNe) with a relatively low ejecta mass of $\sim0.1M_\odot$ (e.g., iPTF 14gqr and SN 2019dge) has been recently reported (Sawada et al. 2022).
From these perspectives, radioisotope $^{56}$Ni is an important indicator of the supernova explosions, which characterizes light curves. Nevertheless, rather than 56Ni, explosion energy has often been paid attention from the explosion mechanism community, since it is, at a glance, easier to estimate from numerical data than the amount of $^{56}$Ni. In this talk, I will discuss the relationship between the radioisotope $^{56}$Ni and the explosion mechanism of supernovae, and "Ni problem", focusing on my own study.