Evolution of ONeMg Core in Super-AGB Stars towards Electron-Capture Supernovae: Effects of Updated Electron-Capture Rate

Understand

Stars with $\sim 8-10~{M}_{\odot}$ evolve to form a strongly degenerate ONeMg core.

• When the core mass becomes close to the Chandrasekhar mass, the core undergoes electron captures on $^{24}$Mg and $^{20}$Ne, which induce the electron-capture supernova (ECSN).
• In order to clarify whether the ECSN leads to a collapse or thermonuclear explosion, we calculate the evolution of an $8.4~M_\odot$ star from the main sequence until the oxygen ignition in the ONeMg core.
• We apply the latest electron-capture rate on $^{20}$Ne including the second forbidden transition, and investigate how the location of the oxygen ignition (center or off-center) and the $Y_e$ distribution depend on the input physics and the treatment of the semiconvection and convection.