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

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 ₌ₒ7-9. 5M_. 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. 510^50 erg and the small ^56Ni mass of 2. 510^-3M_, 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 L210^44 erg/s and can evaporate circumstellar dust up to R10^17 cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L10^42 erg/s and t60-100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by 4 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 E10^48 erg.