3,840°K (cooler) 7,300°K 42,000°K (hotter) B-V Stellar Color Index Temperatures in Kelvin The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields.[12][13] It has a diameter of about 1,392,684 km,[5] about 109 times that of Earth, and its mass (about 2×1030 kilograms, 330,000 times that of Earth) accounts for