Why do stars have different masses?
stars have different masses because they are born that way, unlike humans who continue to gain weight throughout their lifetimes. the difference lies in the fact that stars gain all their mass at birth when they accrete nearby material in their gravitational influence until there is no more material left, whereas humans ‘accrete’ food whenever their appetite says so!
stars generally have masses between one tenth and a few hundred-times the mass of the sun. at the low end, stars with insufficient mass do not burn hydrogen because there is not enough mass to compress the material in their cores to high enough pressures. at the high end, it is not clear what limits the masses of stars. some astronomers claim that there is an upper limit of around 150-times the mass of the sun, although other astronomers believe that there is no limit, or that the limit is higher.
Donald Figer, astronomer at the Rochester Institute of Technology and director of the Future Photon Initiative and the Center for Detectors
the size of a star depends on how much material it absorbed from dust clouds and gases in space