All stars are born with the same basic composition, yet stars can look quite different from one another. Which

Answer 1

one reason stars look different is because stars form in such a large range of masses. a star may be anywhere from 0.08 solar masses to 100 or 120 solar masses. the smaller stars are small and cool, and they are red because they are cool. stars of increasing mass are increasingly hot, and they are increasingly more blue. this is black body radiation. a star changes as it ages also, but stars of different masses change differently. stars generate energy thru nuclear fusion within themselves. all stars begin with hydrogen fusion. the least massive stars never fuse the helium formed from hydrogen. the more massive stars form every nucleus up to and including iron. nuclei more massive than iron are formed in supernovae. the chemical composition of the universe is slowly changing because of stellar fusion.

read these:
http://en.wikipedia.org/wiki/Black_body
http://en.wikipedia.org/wiki/Stellar_evolution
http://en.wikipedia.org/wiki/H-R_diagram

Answer 2

The other answers so far are perfect- size and thus mass will affect the colour of a star.

There is one other thing that plays a part- a star's composition CAN vary. When a star is forming, it is made up from the dust and gas of a dead star that preceeded it. Each star to form from that nebula will have different amounts of hydrogen, helium and so on. This gas-gathering process will also affect the size, as others have mentioned.

Answer 3

Stars are thought to manufacture the heavier elements and have differing compositions. The hot blue stars are young and in this process.

Answer 4

Very good answers. Mass is the biggest contributer to the characteristics of a star.

Answer 5

What's your question? I can probably answer it.
Basic rule:
The bigger a star is (more starting mass of hydrogen), the hotter it burns (whiter, bluer color), the faster it dies (burns thousands or millions of years not billions), and the more violent its death (neutron star or black hole as a result of a supernova explosion as opposed to white or brown dwarf).