Worlds as Real as Ours: Image Processing and Differential Photometry of Transiting Exoplanets

Vanessa Logan


Exoplanets orbit other stars in the same way the Earth orbits the Sun. With over 1,600 exoplanets currently discovered, exoplanet research answers questions concerning solar system and planet formation and the possibility of life on other planets. This thesis focuses on the transit technique for exoplanet detection, in which a passing exoplanet temporarily blocks a small percentage of the light emitted by the star. To capture the transit, a series of images are taken throughout the duration of a transit. The data for this thesis were taken at Lowell Observatory's 31 inch telescope as part of the National Undergraduate Research Observatory (NURO). Over a course of seven nights, sixteen transits were tracked for thirteen different exoplanets. IRAF (Image Reduction and Analysis Facility) routines were used to develop a streamlined image processing software, Photometric Image Reduction Toolkit (PIRT). PIRT reduces the overall time for processing images, improves the registration and magnitude extraction for images, and is designed for astronomers to use with limited IRAF knowledge. The transits were found to be comparable and accurate when compared to previous data collected about the exoplanets. The duration and depth of the transits, the inferred inclination of the exoplanets' orbits and exoplanet radii are consistent with previously reported measurements. Several transits showed variations in transit duration and timing consistent with current trends. The data from this thesis is now part of the international exoplanet collaboration, Exoplanet Transit Database (ETD).