What is the time span for a life cycle of a massive and average star?
Life span could be from a few million years to a trillion years. An average star may have a time span of about a billion years.
A star’s life expectancy depends on its mass. The more massive a star is, the faster it burns up its fuel supply, and the shorter is its life.
The most massive stars burn out and explode in a supernova after a few million years of fusion.
An average star with a mass like the Sun, on the other hand, can continue fusing hydrogen for about 10 billion years.
And if the star is very small, with a mass of say only a tenth of that of the Sun, it can keep fusing hydrogen for up to a trillion years, longer than the current age of the universe.