HYDRODYNAMICAL INSTABILITIES AND MIXING IN SN-1987A - 2-DIMENSIONAL SIMULATIONS OF THE 1ST 3 MONTHS

We present results from numerical simulations of the early stages of the explosion of SN 1987A. Using a two-dimensional cylindrical geometry version of a smooth particle hydrodynamics code, we follow the explosion for 3 months to investigate both early hydrodynamical instabilities and the effect of the subsequent radioactive decay of Ni-56 and Co-56 with half-lives of 6.1 and 77.8 days, respectively. We show that the mixing induced by hydrodynamical instabilities occurring during the first few hours is substantially modified at later time by the radioactive decay of Ni-56 and Co-56. The inner cavity of the expanding supernova remnant fills up with nickel and its decay products thus forming a giant "nickel bubble." The peak velocity of the nickel increases by approximately 30% after the decays. While these results adequately model the core of the observed Fe line profiles, they fail to reproduce the high velocity wings of the spectra.