Exoplanets, planets outside of our solar system orbiting a star, can be observed and analyzed in a variety of ways such as direct imaging and measuring radial velocity. However, the most common method is often the transit method. An exoplanet’s transit is defined as the period of time when the planet passes between its host star and the observer, resulting in some of the light from the star that would typically reach the observer being blocked by the planet. From the observer’s perspective, the star brightness would appear to decrease during this time. If the star is constantly monitored before, during, and after the transit period, a graph of how the brightness changed over time can be constructed and a line called a light curve can be fit to the data and used for analysis.
This project aims to observe exoplanet transits to analyze, confirm, and refine orbital parameters as well as measure our observatory’s capabilities. Transits typically result in a star’s brightness dropping by only about a couple percent, so trying to observe this small difference can help gauge how precise measurements the observatory is able to take. With just light curves, properties such as the transit period, orbital radius and period, an estimate of the planet’s size, and even some atmospheric characteristics can be derived and compared to known data to test for accuracy.
Transits will mainly be observed using relative photometry, which is a method where the brightness of a star is determined by how bright it is relative to some nearby reference star. This means we won’t know the actual brightness of the star we are observing, but it is often not needed to analyze exoplanets. This method helps simplify the data reduction process by not requiring more precise measurements and calibration as well as allowing us to largely ignore the effects of atmospheric extinction
Author: Nick Arnone
Editor: Jacob Rubinstein
Date: 20250305