process has causal agent star gamma-ray stellar radiation Ambiguity exists in the definition of gamma rays. As a rule of thumb, gamma rays have energies above 100 keV, frequencies above 10 exahertz, and wavelengths less than 10 picometers. However, regardless of the energy released, electromagnetic radiation from radioactive decay of atomic nuclei is referred to as "gamma rays". In astronomy, however, gamma rays are defined by their energy, and no production process needs to be specified. A stellar radiation process during which penetrating electromagnetic radiation is emitted from the radioactive decay (gamma decay) of atomic nuclei. envoAstro environmental_hazards gamma-ray solar radiation ionizing stellar radiation gamma-ray radiation