Credit: LANL ISTI/ASC Co-Design Summer School)
The merger of two equal mass neutron stars is simulated using the 3-D code SNSPH. As the two stars merge, their outer edge ejects a spiral of neutron-rich material. The radioactivity in this ejected material is the primary power source for the optical and infrared light observed in the kilonova. A single hyper-massive neutron star remains at the center in a wide field of ejecta material. This hyper-massive neutron star will quickly collapse to a black hole.