The role of heavy ion reactions in astrophysics

Because of the enormous range of temperatures in the "Wide variety of objects that constitute our Universe, it might be supposed that heavy ion reactions between any pair of nuclei might play an important role in astrophysics. no matter how large Z is. However. because high temperatures are generally accompanied by black-body radiation, the high energy tail of the photon spectrum may already photo-produce protons, neutrons, and alpha-particles copiously at temperatures that are still too low for most heavy ion reactions to have significant reaction rates. The protons, neutrons, and alpha-particles produced also react readily with nuclei at these temperatures.