Supernova Explosions of Super-Asymptotic Giant Branch Stars: Multicolor Light Curves of Electron-Capture Supernovae

TL;DR

This paper models the multicolor light curves of electron-capture supernovae from super-asymptotic giant branch stars, revealing characteristic brightness, duration, and dust interaction, and compares these models with observed supernovae.

Contribution

It provides the first self-consistent multicolor light curves for ECSNe based on first-principle explosion simulations, linking theoretical models with observed supernovae.

Findings

Shock breakout luminosity of ~2×10^{44} erg/s

Plateau luminosity of ~10^{42} erg/s lasting 60-100 days

ECSNe can explain characteristics of SN 1054 and SN 2008S

Abstract

An electron-capture supernova (ECSN) is a core-collapse supernova (CCSN) explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass $M_{\rm ms}\sim7-9.5M_\odot$. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a CCSN. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of $1.5\times10^{50}$ erg and the small $^{56}$Ni mass of $2.5\times10^{-3}M_\odot$, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of $L\sim2\times10^{44}$ erg/s and can evaporate circumstellar dust up to $R\sim10^{17}$ cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are $L\sim10^{42}$ erg/s and $t\sim60-100$ days, respectively, and that a plateau is followed by a tail with a luminosity drop by $\sim4$ mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires an ECSN model with a significantly low explosion energy of $E\sim10^{48}$ erg.