What is the exact diameter, radius, and mass of the Sun?
1. Diameter of the Sun at its equator: 1,391,400 kilometers (864,576 miles).
2. Radius of the Sun at its equator: 695,700 kilometers (432,288 miles) (or one solar radius (1 R☉)).
3. Mass of the Sun: 1.9885 × 10^30 kilograms (4.3839 x 10^30 pounds).
What is the sun made of?
The Sun is made up primarily of hydrogen and helium. Hydrogen accounts for about 73% of the Sun's mass while helium makes up about 25% of the Sun's weight. Much smaller quantities of heavier elements, like oxygen, carbon, iron and neon make up the rest.

Most of the elements in the Sun are in plasma form, rather than gas, due to the extreme temperature.