Our sun converts 600 million tons of H to He every second, that is 5 million tons of matter into energy through nuclear fission. However, as the core of the sun continues to shrink the outer layers of the sun move closer and experience a stronger gravitational force. This causes more pressure on the core, which is resulted by increases in the rate at which fusion occurs. Hence the rate at which our sun losses its mass is not continuous. I want to know the mass of our sun when the core is depleted of hydrogen about 5 billion years from now. I also want to know its composition, at present 73% of our sun's mass is Hydrogen and 25% is He.