Answer: A neutron star or a black-hole
Step-by-step explanation:
Supernova is a stage in the life cycle of a massive star. When a massive star dies i.e. when the massive star runs out of fuel, it explodes due to very high pressure. majority of the star's mass is expelled outwards which forms nebula and remaining core either forms a neutron star or a black-hole. An event of super-nova appears very bright in sky.