放ほう射しゃ層そうMeanings1nounradiation zoneastronomyTechnical term in astronomy referring to the region inside the sun where energy is transported primarily by radiation.太たい陽ようの放ほう射しゃ層そうでは、エネルギーが放ほう射しゃによって外そと側がわへ伝つたわる。In the sun's radiation zone, energy is transported outward by radiation.