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.

摘要 本研究为一项教学实验，旨在通过探测宿主恒星的照度变化模拟系外行星观测。为此，我们采用了系外行星行经宿主恒星前方时产生掩食效应的探测技术，即所谓的“凌日法”（transit method）。该技术的原理为：当系外行星掠过恒星盘面时，会使恒星亮度出现小幅衰减，该方法仅适用于轨道平面与观测者视线方向对齐的少量行星。在本教学实验方案中，我们以一盏照明灯充当宿主恒星，以铝箔制成的球体作为待观测的系外行星模型，照度强度探测器则为内置智能手机的勒克斯计（luxmeter）。为模拟系外行星的轨道，我们搭建了圆锥摆（conical pendulum）装置，其摆锤即为该铝箔球体。照度变化的实验数据通过phyphox应用程序获取，并结合凌日法的理论模型进行分析解读。