The Transit Timing and Transmission Spectrum of Hot Jupiter WASP-43 b from a decade of Multi-band Transit Follow-up Observations

TL;DR

This study combines a decade of multi-band transit observations from various sources to refine the parameters and atmospheric understanding of the hot Jupiter WASP-43 b, highlighting the need for high-precision data to resolve modeling degeneracies.

Contribution

It provides a comprehensive analysis of transit timing and transmission spectra of WASP-43 b using diverse datasets, emphasizing the challenges in atmospheric characterization due to modeling complexities.

Findings

No significant orbital decay detected from transit timing variations.

Higher-temperature atmospheric models suggest increased water abundance.

Combining multi-instrument data complicates atmospheric retrievals.

Abstract

We present a new set of 35 transit light curves of the hot Jupiter WASP-43~b, obtained through the SPEARNET network. These datasets were analyzed together with previously published ground-based observations, as well as space-based data from \emph{TESS}, \emph{HST}, and \emph{JWST}, to refine the planetary parameters of WASP-43~b. A total of 188 mid-transit times, measured with \texttt{TransitFit}, were analyzed for potential timing variations. The transit timing variations do not show any significant evidence of orbital decay. Atmospheric retrievals using \emph{HST}/WFC3 G141 transmission spectra suggest that higher-temperature solutions are associated with higher water abundances. However, when these data are combined with observations from ground-based telescopes, \emph{TESS}, and \emph{JWST}, the increased modeling complexity across the broad wavelength baseline presents significant challenges for atmospheric characterization. These results highlight that high-precision, multi-instrument datasets will be necessary to break existing degeneracies in the atmospheric modeling of this target in the future.