Which helium-burning reactions matter most for exploding supermassive stars?

Pair-instability supernovae occur in stars so massive they essentially explode from radiation pressure. The team ran thousands of stellar simulations varying helium-burning reaction rates to pinpoint which temperatures matter most. They found that the triple-alpha and carbon-alpha reactions both show peak sensitivity at 250 million Kelvin, where they shape the carbon-to-oxygen ratio before the explosion—offering a way to constrain nuclear physics from future supernova observations.