TYPES OF STARS

THE main sequence is the point in a star;s evolution during which it maintains a stable nuclear reaction. It is this stage during which star will spend most of its life.Our sun is a main sequence star. A main sequence star will experience only small fluctuations in luminosity and temperature. The amount of time a star spends in this phase depends on its mass large, massive stars will have a short main sequence stage while less massive stars will remain in main sequence much longer very massive stars will exhaust their fuel in only a few hundred million years. smaller stars, like the sun, will burn for several billion years during their main sequence stage. very massive stars will become blue giants during their main sequence.                                                            RED GIANT STARS ,   WHITE DWARF STARS,   BLUE GIANT STARS,   VARIABLE STARS         BINARY STARS,   RED DWARF STARS,   NEUTRON STARS,    SUPERGIANT STARS                 Our galaxy has approximately 250 billion stars and it is estimated by astronomers that there are 100 billion other galaxies in the universe  .  All of the stars comprising the milky way galaxy revolve around the centre of the galaxy once every 200 million years or so. Some stars are 600,000 times as bright as our sun . The oldest star yet discovered is HE which is 13.2 billion years old.