Sun
The Sun is a G2V (G‑type main‑sequence) star at the center of the Solar System whose gravity, radiation, and magnetic activity dominate the heliosphere. It contains about 99.8% of the Solar System’s mass, converts hydrogen to helium by nuclear fusion in its core, and powers Earth’s climate and space weather. Its basic reference properties are standardized by the International Astronomical Union, including a nominal radius of 695,700 km, luminosity of 3.828×10^26 W, and effective temperature of 5772 K.
