The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers , or 109 times that of Earth, and its mass is about 330,000 times that of Earth.
It accounts for about 99.86% of the total mass of the Solar System.
Roughly three quarters of the Sun's mass consists of hydrogen ; the rest is mostly helium , with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.