{
  "id": 17441,
  "title": "'We weren't really looking for' it: Astronomers accidentally discover 2 supernovas that exploded from a single star system in cosmic first",
  "url": "https://urgent.news/2026/07/30/we-werent-really-looking-for-it-astronomers-accidentally-discover-2",
  "topic": "science",
  "section": "Science",
  "published": "2026-07-30T20:25:13.000Z",
  "source": {
    "name": "Live Science",
    "slug": "live-science",
    "url": "https://www.livescience.com/space/in-a-cosmic-first-astronomers-detect-2-sibling-supernovas-that-came-from-a-pair-of-bound-stars"
  },
  "original_language": "en",
  "account": "Researchers may have stumbled upon an unprecedented cosmic event while studying a well-known supernova explosion in the Milky Way. Employing data from NASA's Fermi Gamma-ray Space Telescope over a span of 16 years, scientists detected gamma rays emanating from a supernova remnant called G189.6+3.3, situated adjacent to the more extensively studied IC 443, also known as the Jellyfish Nebula. Their findings suggest that these two remnants are not merely neighbors by chance but could be the remnants of a singular binary star system. This marks the first confirmed case of two supernova remnants originating from the same stellar pair. According to study lead author Miltiadis Michailidis, an astrophysicist at Stanford University, \"We weren't really looking for a binary supernova remnant.\" Initially, they aimed to characterize G189.6+3.3, which was overshadowed by its brighter counterpart, IC 443, one of the best-studied remnants in the galaxy and among the first to show evidence of proton acceleration, a crucial element for cosmic rays. Through the amalgamation of Fermi's gamma-ray data with X-ray, radio, ultraviolet, and optical observations, the team identified an unusual characteristic within G189.6+3.3: a stark division in its structure. The northern portion of the remnant is predominantly filled with accelerated protons, whereas the southern section is dominated by electrons. This unique split, never before observed within a single remnant, was attributed to the environment surrounding the remnant. The northern edge of G189.6+3.3 was found to be pressing against a dense cloud of hydrogen gas, providing a medium for fast-moving protons to collide and generate gamma rays. Conversely, the southern half, lacking this dense material, allowed a different process driven by electrons to dominate. Ultraviolet observations further confirmed that the northern shock wave had slowed after colliding with the dense cloud, supporting this interpretation. Previous studies had already established a connection between IC 443 and the dense hydrogen cloud, suggesting that both remnants were likely at the same distance from Earth. To rule out mere coincidence, researchers simulated 1 million hypothetical binary star systems and computed the probability of two unrelated remnants appearing so close together by chance. The results indicated between a 1 in 1,000 and a 1 in 100 chance, strongly supporting the idea that the two supernova remnants are indeed linked. By estimating the timing of each star's explosion, the team found that the two supernovae likely occurred tens of thousands of years apart, aligning with the scenario where one star in a binary system explodes first, followed by its companion over time. The researchers estimate that the explosions of these stars were separated by tens of thousands of years, a timeframe consistent with one star in a binary pair going supernova before its partner. Michailidis emphasized that this discovery offers valuable insights into the behavior of massive binary stars, their interactions, and their ultimate fates. Looking ahead, the team plans to search for similar binary remnant pairs across the galaxy to deepen our understanding of why this particular system has remained isolated thus far. Michailidis pointed out a significant implication of this finding: it enables astronomers to measure the distance between the centers of the two explosion sites, allowing for a more accurate determination of the energy released during a supernova. Previously, this quantity was estimated through theoretical calculations. \"Now we can actually test it,\" Michailidis remarked.",
  "summary": "Astronomers have identified a supernova remnant beside the well-known Jellyfish Nebula (IC 443), and evidence suggests both are the wreckage of two stars that once orbited each other before exploding separately.",
  "key_points": [
    "Astronomers discovered two supernovas from a single star system by accident.",
    "Gamma rays from supernova remnants G189.6+3.3 and IC 443 suggest a binary star origin."
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}