There is a bottleneck in producing masses higher than4He, because there are no mass-5or mass-8 stable nuclides. For older stars with high densities and high temperatures (T>100 million K), three alpha particles can form12C. This occurs by two alpha particles firstforming8Be, and then8Be reacting with another alpha particle to form12C before8Be candecay back to two alpha particles. a) Explain why this can only happen in very hot stars and high density. b) Calculate how much energy is given up when three alpha particles form12C.