A pair of neutron stars colliding, merging and forming a black hole. Each neutron star squeezes slightly more than the mass of our sun into a volume about 20 kilometers across. Here, a merger with a mass ratio 1.7/1.4 start separated by a distance slightly larger than their diameters. At the moment shown, tides have deformed each star, a common envelope has formed, and the smaller companion is beginning to be disrupted.
Methods: density isosurfaces