gigantic but among stars it's classified as a dwarf. astronomers classify stars based on the spectral characteristics of the light they emit. on a plot of their luminosity versus their color most stars appear in a continuous band known as the main sequence in the midst of it is our sun a fairly average star. the smallest stars are called red dwarfs. they use up their hydrogen so slowly that they're likely to continue burning for trillions of years our sun by contrast is expected to shine for just 12000000000 years. this nebula contains the heaviest star identified by astronomers to date researchers are mystified by how it could accumulate so much mass this