A massive star may have exploded twice, first as a supernova and then hours later as newborn neutron stars collided to create a kilonova, producing the August 2025 gravitational-wave signal and the strange light of AT2025ulz 1.3 billion light-years away in a possible first “superkilonova” that could reveal a new stellar death pathway
A Caltech study in The Astrophysical Journal Letters describes an astronomical mystery with a startling possible solution. A massive star may have exploded as a supernova and produced two unusually small neutron stars. Those dense remnants could have collided hours later, creating a second blast inside the debris of the first. The candidate event, called…
