The three major structural areas of the sun are
Core -- The center of the sun, comprising 25 percent of its radius.
Radiative zone --The section immediately surrounding the core, comprising 45 percent of its radius.
Convective zone -- The outermost ring of the sun, comprising the 30 percent of its radius. Above the surface of the sun is its atmosphere, which consists of three parts
Photosphere -- The innermost part of the sun's atmosphere and the only part we can see.
Chromosphere -- The area between the photosphere and the corona; hotter than the photosphere.
Corona -- The extremely hot outermost layer, extending outward several million miles from the chromosphere.