STELLAR EVOLUTION :
Stars live for a very long time compared to human lifetimes. Even though stellar life-spans are enormous, we know how stars are born, live, and die. All stars follow the same basic series of steps in their lives: Gas Cloud ‡ Proto star ‡ Main Sequence star ‡ Red Giant and/or Supergiant ‡ Horizontal Branch star (only if it has a low mass) ‡ Variable Star (RR Lyra, Cepheid or WVirgins) ‡ Red Giant and/or Supergiant ‡ Planetary Nebula (low mass) or Supernova (high mass star) ‡ Stellar Remnant (white Dwarf, Neutron Star, or Black Hole).
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