Is the orbit of the exoplanet WASP-43b really decaying? TESS and MuSCAT2 observations confirm no detection

TL;DR

This study uses TESS and MuSCAT2 data to analyze the orbital period of exoplanet WASP-43b, finding no evidence of orbital decay over a decade, thus confirming its orbit is stable.

Contribution

The paper provides the most precise measurement to date of WASP-43b's orbital period change, confirming no decay with new high-precision observations.

Findings

No significant orbital decay detected within measurement uncertainties.

Improved orbital parameters for WASP-43b.

Extended baseline of transit timing data over 10 years.

Abstract

Up to now, WASP-12b is the only hot Jupiter confirmed to have a decaying orbit. The case of WASP-43b is still under debate. Recent studies preferred or ruled out the orbital decay scenario, but further precise transit timing observations are needed to definitively confirm or refute the period change of WASP-43b. This possibility is given by the Transiting Exoplanet Survey Satellite (TESS) space telescope. In this work we used the available TESS data, multi-color photometry data obtained with the Multicolor Simultaneous Camera for studying Atmospheres of Transiting exoplanets 2 (MuSCAT2) and literature data to calculate the period change rate of WASP-43b and to improve its precision, and to refine the parameters of the WASP-43 planetary system. Based on the observed-minus-calculated data of 129 mid-transit times in total, covering a time baseline of about 10 years, we obtained an improved period change rate of $\dot{P} = -0.6 \pm 1.2$ ms yr$^{-1}$ that is consistent with a constant period well within $1\sigma$. We conclude that new TESS and MuSCAT2 observations confirm no detection of WASP-43b orbital decay.