A star's mass, temperature and brightness are all highly correlated, as long as the star is on the main sequence. (In fact, that is the definition of "main sequence, that line on the Hertzsprung-Russel diagram where stars spend their lives until they run out of hydrogen to burn) And in general, the later (cooler) the spectral class is of a main sequence star, the longer-lived and fainter it is. Still, stars can evolve off the main sequence towards the end of their lives.
The sun, for example, is currently a main sequence G star, and probably has been that since soon after it first formed, But as it runs out of core hydrogen, it will become brighter and cooler ( a K or M giant ) and eventually wind up its days as a faint but tiny B or A-type white dwarf.
Space/Science » in reply to G star
re: G star