First XRISM results: ten-billion-degree supernova remnant and dust donut at 0.1 light years from black hole

N132D, a supernova remnant located 160,000 light-years away in the Large Magellanic Cloud, is the aftermath of a stellar explosion that occurred about 3,000 years ago. When a massive star ends its life, it undergoes a gigantic explosion, called a supernova, releasing material into space at speeds of several thousand kilometers per second. This explosion creates a shock wave that heats the expelled gas as well as the ambient matter to over a million degrees Celsius, forming a supernova remnant. Supernova remnants provide heavy elements, such as iron, and energy into interstellar space, driving processes like star formation and cosmic-ray generation—crucial to the overall “material and energy circulation” of the Universe, which eventually leads to the formation of planets and life itself.

However, the exact temperature and energy distribution within these remnants have remained elusive. XRISM’s high-resolution spectroscopy has provided a breakthrough in understanding this process. During the first-light observations of N132D, XRISM captured X-ray lines from heavy elements such as silicon, sulfur, and iron, allowing scientists to measure their temperatures precisely. A careful analysis by the research team has revealed that the iron ions have very likely reached temperatures of around 10 billion degrees Celsius.