Simulation of the exoplanet detection by the transit method using the conical pendulum and smartphone

Abstract This work consists of a didactic experiment which aims to simulate the observation of exoplanets by detecting the variation in the illuminace of light from the host star. For this, we use the technique that detect the effect of the exoplanet's shadow when it transits in front of its host star, known as the “transit method”. This technique is based on reducing the brightness of a star when the exoplanet transits in front of its disk, which works with a small percentage of planets whose orbital planes are aligned with the observer's line of sight. In this didactic proposal, a lamp plays the role of the host star, a sphere made of aluminum foil represents the exoplanet to be observed and the illuminance intensity detector is the luxmeter built into a smartphone. To represent the exoplanet's orbit, a conical pendulum was built being its bob the aluminum foil sphere. The results of the variation of illuminance are obtained via the phyphox app and interpreted considering the theoretical model used in the transit method.