Originally posted by sen_almighty
hey ppl, I'm doing a project for senior highskool physics, neways, my topic is colliding stars, i have the process and stuff down, but i can't find things on the physics behind it, like equations used to predict the motion mayobe...or sometohin like keplers laws (i may be soundin stupid to ya'll at this point...) newho, can anyone help me with this please? 
For a highskool project a good idea is to include some photographs of real stuff that is real-world evidence of what you are discussing.
In this case you might consider
http://victorian.fortunecity.com/durer/481/gcframes.html
which has a GALLERY of photographs of GLOBULAR CLUSTERS of stars. These are formed over a billion year time period by millions of close-encounter "collisions" of pairs and triples of stars. If you go to that site you see a "cluster dynamics" button and it says there that these clusters are the best laboratory we have for studying star collisions. Because the spherical distribution of stars and other features are evidence of countless collisions over a long period of time.
People do huge computer simulations of star clusters including a million or so stars, to see how these clusters evolve. How they become spherical.
People sometimes talk about star "mergers" (when they actually splat together) as distinct from "collisions" (where they come close and whip around each other and fly off again).
In globular clusters of stars the actual merger-type events are extremely rare compared with the collisions which are brief gravitational interactions where both stars are deflected by each other and exchange some energy.
Find out from your teacher if it is OK to include this idea of collisions where they interact without merging.
Do you have a picture of a comet doing a one-time pass by the sun in what is called a "hyperbolic" orbit? It just swings close by, is deflected, and flies away----not ever returning. Some comets are non-periodic one-time things. When two stars collide it is rather similar to that hyperbolic orbit comet encounter with the sun.
If your teacher insists on actual merging of the stars then forget I said all this. I apologize in that case. Globular clusters are photogenic things however.
