We constructed a simple demonstration setup to simulate an extrasolar planet and its star revolving around the system's centre of mass. Periodic dimming of light from the star by the transiting planet and the star's orbital revolution simulate the two major ways of deducing the presence of an exoplanet near a distant star. Apart from being a visual aid for those needing help, the setup also elicited unexpected questions and suggestions from students, who achieved a fairly good level of understanding of the basis for the transit and radial velocity methods.

The demonstration set-upThe constructed set-up is shown in figure 1. As mentioned earlier this device can simulate both the radial velocity and the transit method. Thus