Stars Life Cycle

• A star begins as a NEBULA. A nebula is a cloud of dust, hydrogen and helium gasses, which eventually begins to contract under its own gravity.

• The second phase of a star is called the “MAIN SEQUENCE” which is the longest stage of a stars life cycle. Hydrogen fuses into helium, which consequently creates nuclear fusion. Stars temperatures range form 2000C to above 30,000C and colors vary from red to blue-white.

• RED GIANT stage only happens for medium stars and SUPERGIANTS stage only occurs when for large mass stars only. They are large bright stars with cool surfaces. Red Giants develop in the later stages very similar to the sun, as stars begin to run out of hydrogen, they start to cool and expand simultaneously. When the atmosphere of a star becomes very spread out, it slowly dissipates into “planetary nebula, which signifies the end of the cycle.

• RED DWARFS are very faint small stars about 1/10 of the Suns diameter & mass. Red Dwarfs tend to burn extremely slow and have lifespans of 100 billion years.

• The next to last stage of a stars existence is the WHITE DWARF stage. White Dwarfs are small hot stars that are the remaining centerpieces of an old star. Their mass is identical to the Suns, but their luminosity is a small percentage of the Sun.

• The actual demise of a star is called the SUPERNOVA! This is a ginormous explosion wherein a star collapses after it uses up all its fuel source. Supernova’s can obtain the brightness of 100 million stars for a short time.