Through a series of simulations, an international team of researchers has determined that some mergers of neutron stars produce radiation that should be detectible from Earth. When neutron stars of unequal mass merge, the smaller star is ripped apart by tidal forces from its massive companion (left). Most of the smaller partner's mass falls onto the massive star, causing it to collapse and to form a black hole (middle). But some of the material is ejected into space; the rest falls back to form a massive accretion disk around the black hole (right).
Adapted from figure 4 in "Accretion-induced prompt black hole formation in asymmetric neutron star mergers, dynamical ejecta and kilonova signals." Bernuzzi et al., Monthly Notices of the Royal Astronomical Society.