Transcript: The steep relationship between mass and luminosity for main sequence stars has an important consequence for the lifetime of the stars. Consider a star that’s a tenth the mass of the Sun. In round numbers the luminosity is ten to the minus four times the luminosity of the Sun. Thus the size of the fuel reservoir is ten times smaller, but the rate of evolution is ten thousand times smaller. This means the star will last about a thousand times longer than the Sun. Instead of a total main sequence life of ten to the ten years, we have a total main sequence life of ten to the thirteen or ten trillion years. Compare it to the other end of the main sequence. A star of a hundred times the mass of the Sun in round numbers has a luminosity a million times that of the Sun. Although the fuel reservoir is a hundred times larger than the Sun, the rate of burning the fuel is a million times larger which means the star lasts ten thousand times less long than the Sun. Instead of a main sequence lifetime of ten billion years, we have a main sequence lifetime of roughly a million years.