First known binary-star pair where both stars exploded as supernovae

Astronomers analyzing 16+ years of multiwavelength data (including NASA’s Fermi gamma-ray observations) identify IC 443, the Jellyfish Nebula, and the nearby remnant G189.6+3.3 as a likely first binary-star supernova pair: two massive stars that exploded within the same interstellar cloud, about 30–50 light-years apart. IC 443 is estimated at 8,000–9,000 years old, while G189.6+3.3 is older (20,000–110,000 years). The odds of a random alignment are ~1 in 1,000, suggesting a genuine binary progenitor and providing insights into how massive binary stars evolve and end their lives.