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New simulations performed on a NASA supercomputer are providing scientists with the most comprehensive look yet into the maelstrom of interacting magnetic structures around city-sized neutron stars in the moments before they crash. The team identified potential signals emitted during the stars' final moments that may be detectable by future observatories.
"Just before neutron stars crash, the highly magnetized, plasma-filled regions around them, called magnetospheres, start to interact strongly. We studied the last several orbits before the merger, when the entwined magnetic fields undergo rapid and dramatic changes, and modeled potentially observable high-energy signals," said lead scientist Dimitrios Skiathas, a graduate student at the University of Patras, Greece, who is conducting research for the Southeastern Universities Research Association in Washington at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
A paper describing the findings published Nov. 20, 2025, in the The Astrophysical Journal.
Neutron star mergers produce a particular type of GRB (gamma-ray burst), the most powerful class of explosions in the cosmos.
Most investigations have naturally concentrated on the spectacular mergers and their aftermaths, which produce near-light-speed jets that emit gamma rays, ripples in space-time called gravitational waves, and a so-called kilonova explosion that forges heavy elements like gold and platinum. A merger observed in 2017 dramatically confirmed the long-predicted connections between these phenomena - and remains the only event seen so far to exhibit all three.
Neutron stars pack more mass than our Sun into a ball about 15 miles (24 kilometers) across, roughly the length of Manhattan Island in New York City. They form when the core of a massive star runs out of fuel and collapses, crushing the core and triggering a supernova explosion that blasts away the rest of the star. The collapse also revs up the core's rotation and amplifies its magnetic field.
