ORBITING BINARY STARS

Astronomy 1101/1103 __________________________ Yervant Terzian/Terry Herter

You need a JAVA enabled browser to view this simulation. A simplified derivation of the magnitude of the reflex motion of the star due to an orbiting planet can be found here.

Allows you to set the masses, orbital separation, orbital eccentricity, the inclination angle to our line of sight, and the angle of the nodes of an orbiting star pair. You see the privileged (from above the orbit) and the earth view of the system (which depends on the inclination angle). The observed velocities of the two stars, and the Doppler shifted spectral lines (as seen against the combined continuum from the two stars) are also shown in the upper rightbox. The spectral lines associated with each star are indicated and the unshifted line positions are also marked. The movement of the spectral lines against the continuum has been greatly exaggerated for display purposes, and the difference in brightness of the two stars has been ignored.

We have the following definitions:

 Mass 1 or Mass 2 The mass of each of the two stars. Separation The distance between the two stars in solar radii. Eccentricity Eccentricity of the orbit Inclination angle Angle of the orbital plane of the stars to our line-of-sight. 0o - face on90o - edge on Note that this is opposite from the Eclipse simulation - we'll fix this in the future. Node angle Angle of the major axis as measured in the orbital plane (see privileged view)
• Adjust the star masses, separation, etc
• Click "enter" to update the simulation parameters.
• Use "pause" to start and stop the simulation, ifdesired.
• If the picture is messed up at anytime, use "enter"to redraw it
• The number between the "<=" and "=>"buttons, is the rough time (in seconds) it takes the simulation to complete an orbit. Make this number larger or smaller by clicking the "arrow" buttons.
• Change the eccentricity to 0.7.
• Change the inclination angle to 45o.
• Change the node angle to 45o.
• Click "Enter" to restart simulation with these values.