Effects of Jet-like Explosion in SN 1987A

Abstract

We study the effects of jet-like explosion in SN 1987A. Calculations of the explosive nucleosynthesis and the matter mixing in a jet-like explosion are performed and their results are compared with the observations of SN 1987A. It is shown that the jet-like explosion model is favored because the radioactive nuclei 44Ti is produced in a sufficient amount to explain the observed bolometric luminosity at 3600 days after the explosion. It is also shown that the observed line profiles of Fe[II] are well reproduced by the jet-like explosion model. In particular, the fast moving component travelling at (3000-4000) km/s is well reproduced, which has not been reproduced by the spherical explosion models. Moreover, we conclude that the favored degree of a jet-like explosion to explain the tail of the light curve is consistent with the one favored in the calculation of the matter mixing. The concluded ratio of the velocity along to the polar axis relative to that in the equatorial plane at the Si/Fe interface is about 2:1. This conclusion will give good constraints on the calculations of the dynamics of the collapse-driven supernova. The asymmetry of the observed line profiles of Fe[II] can be explained when the assumption of the equatorial symmetry of the system is removed, which can be caused by the asymmetry of the jet-like explosion with respect to the equatorial plane. In the case of SN 1987A, the jet on the north pole has to be stronger than that on the south pole in order to reproduce the observed asymmetric line profiles. Such an asymmetry may also be the origin of the pulsar kick. When we believe some theories that cause such an asymmetric explosion, the proto -neutron star born in SN 1987A is moving in the southern part of the remnant.