Binary Stars

Astronomers discover planets outside our solar system by detecting the "wobble" in the star that the planet orbits.  Use the simulation below to understand why a star "wobbles" due to the orbit of a planet.  Consider the relative mass difference between a planet and star in your explanation.  For instance, set the mass ratio=100 and the initial speed of the planet = 0.4 x 10⁶ m/s for a nice illustration of the "wobble" of the star.

If the mass ratio is 100, what is the mass of the star? (Hint: consider conservation of energy.)  The coordinates of the animation are given in units of Mm or 1 x 10⁶ m.  You may have to adjust the time step in the animation to display the best animation.

are scriptable Java Applets written by Wolfgang Christian of Davison College.