What is the relationship between the size of a star and its life span?
The more massive the star, the shorter is its life span. Stars having much more mass than the Sun burn their fuel prodigally in a flaming youth and hurry to an early death. For example, a star ten times as massive as the sun radiates a thousand times as much power, but survives for only a hundred million years. To sustain its greater weight, its nuclear furnace must burn hotter. The rate of nuclear fusion is very sensitive to temperature; at 20 million degrees the nuclear fuel is consumed 30,000 times faster than at million degrees.
What are spectroscopic binaries?
In spectroscopic binary systems the two component stars are usually too close together to be discerned separately, but they can be identified by spectroscopic analysis of light from the binary system.