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Binary Star Integrator (2D)
Help File


  • HELP. Displays this help screen. To exit, click one of the Exit Help buttons located at the top and bottom of this screen.
  • INTEGRATION TIME. Here you specify how long into the future the orbit should be followed. Be careful in choosing this parameter as it is directly correlated to how long you will wait before seeing a plot! A good strategy is to try a short integration time first to get an idea of how fast the program is.

    Orbit of Binary Star

  • MASS OF STAR 1. A Solar Mass is the mass of the Sun. So a "1.0" entered here means the star will have the same mass as our Sun, a "2.0" means the star has twice this mass, etc.
  • MASS OF STAR 2. Same as above.
  • AVERAGE DISTANCE BETWEEN THE STARS. The average distance between the stars is also the orbital semimajor axis. An AU is the Earth-Sun distance.
  • ECCENTRICITY OF STARS' ORBITS. The eccentricty gives the shape of the stars elliptical orbits. The eccentricity must be between 0 and 1. An eccentricity of 0.0 will produce an initially circular orbit; larger eccentricities correspond to narrower ellipses.

    Orbit of the Planet

  • SEMIMAJOR AXIS. The semimajor axis is half the long axis of the initial elliptical orbit.
  • ECCENTRICITY. The eccentricity gives the shape of the third body's elliptical orbit; it must be a value between 0 and 1. An eccentricity of 0.0 will produce an initially circular orbit; larger eccentricities correspond to narrower ellipses.
  • ARGUMENT OF PERICENTER (). The argument of pericenter is the angle measured from a reference point () to the pericenter (P) of the orbit with the center chosen above as the vertex of the angle.
  • TRUE ANOMALY (). This parameter specifies the angle between pericenter (P) and the position of the planet along its orbit.


  • SUBMIT FORM. Send the parameters that you have chosen to the orbital integration program!
  • LOAD DEFAULTS. Set all parameters back to their default values.

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