Binary Star Simulator

This applet simulates two objects orbiting each other. It may take a few moments to load.

On the left-hand side of the applet, the controls are:
  1. M1 and M2: relative masses of the two objects
  2. a: semimajor axis of the larger orbit
  3. e: eccentricity of the orbit
  4. i: inclination angle of the orbits (relative to our view from Earth)
  5. w: sets the rotation angle of the semimajor axis
  6. A top-down view of the orbits.
 On the right-hand side of the applet, you see:
  1. A way to control the speed of the simulation
  2. The period of the orbit, in years
  3. A plot of the objects' radial velocities vs time -- that is, how fast the objects are moving toward or away from us.
  4. The motion of absorption lines in the objects' spectra. Because they move toward or away from us as they orbit, their spectra are redshifted or blueshifted accordingly.
  5. The orbits as viewed from Earth.

Written by Terry Herter, Cornell, and used with permission.