On the parameter refinement of inflated exoplanets with large radius uncertainty based on TESS observations

TL;DR

This study refines the planetary radii and orbital parameters of ten inflated exoplanets using TESS data, improving measurement precision and resolving discrepancies in previous literature.

Contribution

It introduces a method combining transit light curve fitting and MCMC analysis to enhance parameter accuracy for exoplanets with uncertain radii.

Findings

Refined planetary radius of WASP-140 b by 12%.

Improved the precision of radius uncertainty for WASP-140 b by up to 86%.

Resolved a radius discrepancy for WASP-93 b.

Abstract

We revisited ten known exoplanetary systems using publicly available data provided by the Transiting Exoplanet Survey Satellite (TESS). The sample presented in this work consists of short period transiting exoplanets, with inflated radii and large reported uncertainty on their planetary radii. The precise determination of these values is crucial in order to develop accurate evolutionary models and understand the inflation mechanisms of these systems. Aiming to evaluate the planetary radius measurement, we made use of the planet-to-star radii ratio, a quantity that can be measured during a transit event. We fit the obtained transit light curves of each target with a detrending model and a transit model. Furthermore, we used emcee, which is based on a Markov chain Monte Carlo approach, to assess the best fit posterior distributions of each system parameter of interest. We refined the planetary radius of WASP-140 b by approximately 12%, and we derived a better precision on its reported asymmetric radius uncertainty by approximately 86% and 67%. We also refined the orbital parameters of WASP-120 b by 2$\sigma$. Moreover, using the high-cadence TESS datasets, we were able to solve a discrepancy in the literature, regarding the planetary radius of the exoplanet WASP-93 b. For all the other exoplanets in our sample, even though there is a tentative trend that planetary radii of (near-) grazing systems have been slightly overestimated in the literature, the planetary radius estimation and the orbital parameters were confirmed with independent observations from space, showing that TESS and ground-based observations are overall in good agreement.