Swirling gas sets pulsar spinning in supercomputer simulation.
This visualization of a simulated supernova is helping to reveal why pulsars spin so fast. Pulsars are neutron stars that emit beams of electromagnetic radiation as they whirl around many times per second — a rate that astrophysicists have struggled to explain. Pulsars are thought to form in core-collapse supernovae, the explosive deaths of stars at least eight times the mass of the Sun, in which the iron core collapses in on itself.
In 2007, computer simulations suggested that the stars don't explode in perfectly smooth spheres (J. M. Blondin and A. Mezzacappa Nature 445, 58–60; 2007). This latest visualization, created by Hongfeng Yu, a computer scientist at Sandia National Laboratories in Livermore, California, shows the entropy of the gases in the dying star's core, revealing the immense swirling currents that originated as tiny perturbations (gases with the highest entropy are yellow, followed by green and then purple). The currents "spin up the proto-neutron star, just like pulling a string on an old spinning top", says Bronson Messer, an astrophysicist at Oak Ridge National Laboratory in Tennessee, who contributed to the research. The work incorporates a new visualization technique, developed at Argonne National Laboratory outside Chicago, Illinois, which runs and visualizes the simulation directly on a Blue Gene/P supercomputer.