a cloud of interstellar gas and dust; the gas is mostly hydrogen and the dust is mostly silicon and carbon
main sequence star
star at a hydrostatic equilibrium, where the forces of gravvity trying to collapse the star are balanced by the energy released from the fusion trying to blow the star apart
the process of light nuclei combining to form heavier nuclei
The life cycle of a star depends on the mass at the start of fusion with a very small dependence on chemical composition. Massive stars evolve quicker than light stars.