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

TL;DR

This paper uses TESS data to analyze transits of WASP-12 b, refining its orbital parameters and confirming its inflated size, demonstrating TESS's effectiveness for detailed exoplanet characterization.

Contribution

The study provides updated transit parameters and refined ephemeris for WASP-12 b using TESS data, with no detected transit timing variations.

Findings

Refined orbital period and epoch for WASP-12 b

Confirmed the planet's highly inflated radius

No significant transit timing variations detected

Abstract

We present a detailed transit photometric analysis of the ultra-hot Jupiter WASP-12 b using data from the Transiting Exoplanet Survey Satellite (TESS). The study is based on publicly available calibrated light curves and target pixel files accessed through the Mikulski Archive for Space Telescopes (MAST) cloud infrastructure. After extracting and normalizing the photometric time series, the light curve was phase-folded using an initial ephemeris and modeled with a physical transit model to determine the system's geometric parameters. From the transit modeling, we measure the planet-to-star radius ratio, orbital inclination, impact parameter, and transit duration. Adopting stellar parameters from the literature, we derive the planetary radius and transit depth, confirming the highly inflated nature of WASP-12 b. Individual mid-transit times were measured and used to refine the orbital ephemeris through a weighted linear fit. The resulting refined orbital period and reference epoch improve the predictive accuracy of future transit times over the TESS observational baseline. An observed-minus-calculated (O-C) analysis reveals no statistically significant transit timing variations, indicating that the timing data are consistent with a linear ephemeris within the measurement uncertainties. This work demonstrates the capability of TESS photometry to provide precise transit characterization and ephemeris refinement for well-studied exoplanet systems, and provides updated parameters that are relevant for future atmospheric and dynamical investigations of WASP-12 b.