The First Stage: The Nebula http://rigel.csi.cuny.edu/rowan/lectures/Hubble%20Nebulae_files/HelixNebula-HST.jpg A nThe nebula is a cloud of gas and dust. It is not yet a star.
The Protostar http://www.williamsclass.com/EighthScienceWork/ImagesEighth/Protostar.jpg
Brown Dwarf A brown dwarf occurs if the protostar is too small to ignite fusion. http://chandra.harvard.edu/photo/2003/twa5b/twa5b_dwarf_ill.jpg
Main Sequence http://www.astronomyexpert.co.uk/images/9392.jpg A protostar gets enough mass to ignite fusion. All main sequence stars fuse hydrogen. Stars spend most of their life in the main sequence stage.
Red Giant http://home.comcast.net/~van.etten/Support/Red%20Giant.jpg A red giant is formed when a small to medium sequence star runs out of hydrogen and begins fusing helium.
Planetary Nebula http://rigel.csi.cuny.edu/rowan/lectures/Hubble%20Nebulae_files/HelixNebula-HST.jpg A red giant completely stops fusing helium and the outer layers of the star are driven away.
White Dwarf http://www.nasa.gov/centers/goddard/images/content/207358main_whitedwarf_20080102_HI1.jpg White Dwarf The white dwarf is the leftover core of a star. It is extremely dense. It may be the size the earth but has half the weight of the sun.
Black Dwarf A white dwarf cools off after trillions of years and eventually stops emitting light. http://library.thinkquest.org/3103/nonshocked/topics/blackdwarfs/images/blackdwarfimg.gif
Massive Main Sequence https://segue.atlas.uiuc.edu/uploads/ryemm2/blue%20main%20sequence.jpg Massive main sequence stars burn more quickly than small to medium mass main sequence stars because they fuse more hydrogen.
Red Super Giant Red SUPERGIANT http://solarsystem.nasa.gov/multimedia/gallery/prominence.gif Red Super giants occur when massive main sequence stars run out of hydrogen and start fusing helium, carbon, oxygen, etc.
SUPERNOVA! http://d21c.com/sookietex/space_supernova.jpg When fusion stops, the star collapses and creates a huge explosion.
Neutron Star http://media.arstechnica.com/journals/science.media/neutron_star.jpg The super dense core left over after a supernova is called a neutron star.
Black Hole BLACK HOLE http://startswithabang.com/wp-content/uploads/2008/05/ashtekar_blackhole.jpg Stars with masses 25-50 times the mass of the sun form a black hole after the supernova. Other stars turn into Neutron Stars. Nobody knows what happens to things after they go into a black hole.