At the center of the Sun lies its core, where hydrogen fuses into helium, creating energy.
The core is estimated to be about 280,000 miles (450,000 km) in diameter.
The core of the Sun is the only location in the Sun that produces a significant amount of heat through fusion.
From the core out, there is the radiative layer, more than 167,000 miles (278,000 km) deep; the convection layer, about 125,000 miles (200,000 km) deep; and the photosphere, about 190 miles (300-500 km) deep, which we see as the Sun’s surface.
The Sun’s atmosphere is made of the chromosphere, nearest the surface, and the outer corona.