Number 210 (Story #2), January 13, 1995 by Phillip F. Schewe and Ben Stein|
THE INTERIOR LIFE OF SUPERNOVAS has been made visible through sophisticated supercomputer simulations. The new models show what happens when the massive outer portion of a dying star falls in on the blizzard of neutrinos streaming out of the just-collapsed core. Older models, tending to look only at one-dimensional, pencil-beam sections of the evolving supernova explosion, were unsatisfactory since they too often predicted that supernovas would stall out, not for want of energy but because the tremendous energy stored in the nascent explosion (10**53 ergs) could not effectively be transmitted to the cooler stellar matter above. At the AAS meeting, Adam Burrows and Willy Benz of the University of Arizona and Marc Herant of Los Alamos showed off their multi-dimensional models allowing colossal convective plumes of rising hot material and sinking cool material to interpenetrate, facilitating a more efficient movement of explosion energy. (Herant compared all of this to heating a thick sauce in a pan. Left unstirred, the sauce will burn on the bottom and be cool on top. Stirring allows heat to get to the top.) Not only does the complex mixing permit the outward-going shock wave to proceed on schedule---eventually ripping apart the outer envelope of the star---but it helps to explain other features of supernovas poorly handled in older models. These features include the dispersal of heavy elements in the subsequent debris blown into space, the overall asymmetric shape of supernovas, and the observed sideways recoil velocities (amounting to hundreds of km/sec) imparted to the pulsar remnant of some supernovas.