the smaller the starting mass of a star is the longer it will live
In the clouds of dust and gases nebula. Hydrogen atoms forms a spinning cloud of gas and eventually pulls more hydrogen gas to the spinning cloud. As it spins hydrogen atoms start to collide with each other and hydrogen gas heats up. When this reaches ##15000000^@C## nuclear fusion begins and causes to form a new star or protostar.
Once a protostar forms its life cycle is fixed.
Medium-sized star ##rarr##red giant or super giant
if a star started with a small mass##rarr## main-sequence stars##rarr##white dwarf##rarr##black dwarf
if a star is a low mass red giant##rarr##white dwarf ##rarr##black dwarf (dead star)
if a star is super massive##rarr## super red giant##rarr##supernova very high mass##rarr##Black Hole
if a star is massive red giant##rarr##supernova high mass##rarr##neutron star
Remember that after a supernova another nebula will form. Neutron stars and blackholes are the core of a star.
http://pics-about-space.com/life-cycle-of-stars-nasa?p=2