Transit Photometry and Ephemeris Refinement of WASP-12 b Using TESS Data

Abstract

In this study, we conduct a thorough analysis of transit photometry for the ultra-hot Jupiter, WASP-12 b, using observations acquired by the Transiting Exoplanet Survey Satellite (TESS). The study makes use of light curves and target pixel files, which have been made available through the Mikulski Archive for Space Telescopes (MAST) platform. Following the extraction and normalization of the photometric time-series data, a physical-transit model was applied to the phased light curve to estimate the geometric parameters of the system. Based on the results of the transit model, we estimate the radius ratio, orbital inclination, impact parameter, and duration of the transit. By assuming the stellar parameters reported in literature, we derive the planetary radius and transit depth of the system. We then extract the individual mid-transit times and apply a weighted linear fit to obtain a refined ephemeris. The resulting refined orbital period and reference epoch yield a more accurate prediction of future transit times. A transit-timing-variation analysis was done using an O-C diagram to evaluate the deviation of the timings from a linear ephemeris. There is no evidence for transit timing variations in the dataset used. This study shows how publicly available archival data such as photometry from TESS, and using remote platforms and cloud services (e.g. MAST/TIKE), can help analyse and refine the parameters of well-studied exoplanets, which is useful for further investigation of their atmospheres and dynamics, such as in the case of WASP-12 b.