A closer look at potential exoplanet targets from the Nooitgedacht Observatory

MSc (Astrophysical Sciences), North-West University, Potchefstroom Campus

Exoplanet surveys like KELT and TESS often require follow-up observations with a traditional, ground based telescope to confirm whether a potential candidate is indeed an exoplanet or not. The optical telescope at the Nooitgedacht Observatory is ideal for these types of observations. During a transit event, there is a reduction in the brightness of the star, caused by the planet obstructing the light coming from the star. The amount of light blocked by the planet is called the transit depth, and is expressed in parts-per-thousand. The aim of this study was to determine the minimum transit depth observable with the equipment available at the Nooitgedacht Observatory. Six observations were conducted on known planetary-systems and one for a potential exoplanet target. The images were calibrated, aperture and differential photometry was conducted and the flux of the target was extracted from the images. The flux was normalised and a transit model fit was applied to the data with parameters found in literature, to obtain light curves. The resulting models and light curves of the transit events are presented. From the models the radius of the exoplanet, the stellar density of the host star and the inclination angle of the planetary-system were determined, which were compared to results found in literature. From the accuracy of the models obtained, it was concluded that the soft limit for the minimum transit depth an exoplanet candidate can have to be detected by the Nooitgedacht telescope, is 10 parts-per-thousand. The hard limit could not be determined due to observational issues. During the course of the project, issues regarding the pointing, tracking and focus of the telescope came to light and recommendations were made on how the issues could be resolved.

Masters