written by Mario Belloni

The Exoplanet Detection: The Radial Velocity Method model simulates the detection of exoplanets by using the radial velocity method and the Doppler effect. In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law.  The radial velocity of the star is determined from the velocity of the exoplanet.  This velocity is then used to calculate the Doppler shift of the Fraunhofer lines of the star.  In practice it is the Doppler shift of the Fraunhofer lines of the star that are detected and from this the radial velocity is inferred.  From this the mass and orbital period and average exoplanet-star separation are determined.  In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) and from space (overhead view), and with the star and exoplanet sizes not shown to the scale of the orbit.  In addition, the Fraunhofer lines are shown.  The radial velocites of stars are such that the Doppler shifts are small, to compensate you may snap to the Na line and use the right-hand side slider to zoom in on that line to see wavelength shift.  The mass of the exoplanet (relative to the mass of Jupiter), the average star-exoplant separation (in AU), and the inclination of the system relative to Earth can be changed.

The simulation uses Java 3D, if installed, to render the view the star and exoplanet. If Java 3D is not installed, the simulation will default to simple 3D using Java.

• Download ejs_astronomy_exoplanet_doppler.jar - 1959kb Java Archive File

Last Modified June 6, 2014

This file has previous versions.

The source code zip archive contains an XML representation of the  Exoplanet Detection: The Radial Velocity Method Model.   Unzip this archive in your Ejs workspace to compile and run this model using Ejs.

• Download ejs_astronomy_exoplanet_doppler.zip - 30kb Compressed File

Published June 29, 2010
Last Modified June 6, 2014

This file has previous versions.