Description

This program simulates the detection of exoplanets by using the transit method. In this method, the light curve from a star, and how it changes over time due to exoplanet transits, is observed and then analyzed.

In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law. When the exoplanet passes in front of the star (transits), it blocks part of the starlight. This decrease in starlight is shown on the graph. If the exoplanet is close enough to the central star, and has sufficient reflectivity, or albedo, it can reflect enough of the starlight to be seen on the light curve.

In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) but magnified greatly, and with the star and planet sizes not shown to the scale of the orbit. The radius of the central star (relative to the radius of Sun),semi-major axis of the exoplanet (in AU), radius of the exoplanet (relative to the radius of Jupiter), the exoplanet's albedo (reflectivity), and the inclination of the system relative to Earth can be changed.

Since 1999, over 4,000 exoplanets have been found, with over 2,000 confirmed via the transit method by primarily space-based telescopes such as CoRoT and Kepler. These exoplanets have radii varying from 0.15 to 1.80 RJupiter, semi-major axes varying from 0.015 to 0.5 AU, and orbital periods varying from 1 to 111 days. They also have albedos ranging from 0.10-0.20 (or 10% - 20%). For comparison, Jupiter's albedo is 0.52 (or 52%).

This simulation is part of a sequence of simulations used to introduce students to the detection of exoplanets. Additional simulations can be found on the OSP ComPADRE site.