* Astronomy

The movie shows the visualisation of a supercomputer simulation of the birth of a neutron star and the onset of the supernova explosion of a star with about 11 times the mass of the Sun. The neutron star is as an extremely compact object that forms in the deep interior of the dying massive star when the stellar core collapses under the pull of its own gravity within fractions of a second. It encompasses more than a solar mass in finally the volume of a big city and is visible first as whitish, then blue, in transparent sphere at the center. A shock wave (discernable as surface of a sharp transition between yellow/red and bluish colours) is launched when the infalling stellar matter (visible as extended blue cloud around the neutron star) crashes supersonically onto the surface of the nascent neutron star. The shock-heated stellar gas envelopes the neutron star as a red and orange shell. The intense flux of neutrinos, weakly interacting elementary particles that are abundantly radiated from the neutron star, further heats the postshock layers to higher temperatures and thus triggers the onset of violent convective overturn. Roughly a tenth of a second after its launch the shock develops pronounced asphericity, partly due to the convective perturbations, partly because of a generic instability to nonradial deformation (visible by dipolar oscillations of the shock). More infalling stellar gas (blue) is channelled towards the neutron star in downflows while heated gas (red and yellow) is rising against the infalling matter due to buoyancy. Thus the shock is pushed to larger and larger radii. Finally, the flow arranges itself into two huge, inflating polar lobes that are alternatingly fed by powerful waves of fresh, neutrino-heated gas from equator-near downflows. By the end of the movie the largely aspherical shock rushes outward with a speed of 10,000 kilometres per second (requiring a zoom-out in the movie) and is going to expel the outer layers of the dying star in the supernova explosion.

Credit & Copyright: Babak Tafreshi (TWAN)