* Astronomy

Title: Supernova Explosions of Super-Asymptotic Giant Branch Stars: Multicolor Light Curves of Electron-Capture Supernovae
Authors: Nozomu Tominaga, Sergei I. Blinnikov, Ken'ichi Nomoto

An electron-capture supernova (ECSN) is a core-collapse supernova explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass M_{ms} ~7-9.5 solar masses. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulation. This allows us to derive a first self-consistent multicolour light curves of a core-collapse supernova. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 x 10^{50} erg and the small ^{56}Ni mass of 2.5 x 10^{-3}solar masses, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolour 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~ ~2 x 10^{44} erg/s and can evaporate circumstellar dust up to R~10^{17} cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L~10^{42} erg/s and t~60-100 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 a ECSN model with a significantly low explosion energy of E~10^{48} erg.

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