a catalyst makes a reaction more likely to occur but does not get used up in the process. carbon is the catalyst in the cno cycle, which makes the cno cycle far more efficient at fusing hydrogen than the p-p chain. in addition, recall that more massive stars have hotter cores, which is necessary for the outward thermal pressure to balance the greater inward gravitational pressure. the higher the temperature, the faster the particles in the core are moving. what effects will the efficient fusion and high core temperatures have on high-mass stars?
