Investigation of an orbital decay and global modeling of the planet WASP-43 b

TL;DR

This study investigates potential orbital decay in the exoplanet WASP-43 b through transit timing analysis, combining ground and space observations, and provides refined system parameters while noting the current data's limitations for confirming decay.

Contribution

It offers a comprehensive global model of WASP-43 b using combined photometric and radial velocity data, and explores possible orbital decay with new constraints on tidal quality factors.

Findings

Transit timings mostly consistent with a linear ephemeris.

Hints of orbital period decrease are statistically insignificant.

Estimated lower limit for the tidal quality factor Q'_* > 4.01×10^5.

Abstract

WASP-43 b is one of the most important candidates for detecting an orbital decay. We investigate pieces of evidence for this expectation as variations in its transit timings, based on the ground and space observations. The data set includes the transit observations at the TUBITAK National Observatory of Turkey and Transiting Exoplanet Survey Satellite (TESS). We present a global model of the system, based on the most precise photometry from space, ground, and archival radial velocity data. Using the homogenized data set and modeled light curves, we measure the mid-transit times for WASP-43 b. Our analysis agrees with a linear ephemeris for which we refine the light elements for future observations of the system. However, there is a negative difference between the transit timings derived from TESS data in two sectors (9 and 35) and a hint of an orbital period decrease in the entire data set. Both findings are statistically insignificant due to the short baseline of observations, which prevents us from drawing firm conclusions about the orbital decay of this ultra-short-period planet. However, assuming the effect of this decrease of the period in the planet's orbit, we derive a lower limit for the reduced tidal quality factor as Q'_* > (4.01 +_ 1.15). 10^5 from the best-fitting quadratic function. Finally, we calculate a probable rotational period for this system as 7.52 days from the out-of-transit flux variation in the TESS light curves due to spot modulation.