Overview
- The Cassiopeia A remnant shows clear X‑ray lines of chlorine and potassium at abundances far above standard supernova model predictions.
- XRISM’s Resolve microcalorimeter delivered about ten times sharper energy resolution than earlier X‑ray detectors, enabling the detections.
- The result provides the first observational evidence that one supernova can supply enough of these odd‑Z elements to match cosmic inventories.
- Researchers attribute the elevated yields to strong internal mixing in massive stars, a developing explanation that includes rotation, binary effects, or shell mergers.
- The team will survey additional supernova remnants with XRISM to determine whether Cassiopeia A is representative or an outlier, with findings reported in Nature Astronomy.