Scientists spot evidence of 2 huge companion stars that blew up

Astronomers have identified evidence of two massive companion stars that both exploded as supernovae, a phenomenon never before observed. The discovery, based on data from NASA's Hubble Space Telescope and other observatories, reveals a pair of stellar remnants moving away from each other at high speeds, suggesting they were once part of a binary system that ended in twin explosions.

The affected objects are two neutron stars—the ultra-dense cores left after supernovae—located in the galaxy M81, about 11.5 million light-years from Earth. Their motion and the surrounding debris clouds indicate they originated from the same stellar nursery and exploded within a few million years of each other. This matters because it challenges existing models of binary star evolution, which typically predict that only one star in a pair would explode, while the other collapses into a black hole or becomes a white dwarf.

Specific data from the study, published in Nature on February 12, 2025, show the neutron stars are moving at roughly 1,000 kilometers per second, with one trailing a tail of hot gas. The team, led by researchers at the University of California, Berkeley, used the Chandra X-ray Observatory and the Very Large Array to confirm the objects are neutron stars, not black holes.

Background: Binary star systems are common, but until now, no confirmed pair of supernova progenitors had been found. Earlier searches turned up single neutron stars or black holes, but never two that both exploded. The discovery was made possible by comparing archival images spanning 20 years, which revealed the stars' rapid motion.

Next steps include further observations with the James Webb Space Telescope to study the chemical composition of the debris and refine models of how such systems evolve. The findings may also help explain the origin of fast-moving neutron stars and the rate of supernovae in the universe.