2024MNRAS.535L...7Y

Hot Jupiters should initially form at considerable distances from host stars and subsequently migrate towards inner regions, supported directly by transit timing variation (TTV). We report the TTV of K2-237b, using reproduced timings fitted from Kepler K2 and TESS data. The timings span from 2016 to 2021, leading to an observational baseline of 5 yr. The timing evolution presents a significant bias to a constant period scenario. The model evidence is evaluated utilizing the Bayesian Information Criterion (BIC), which favours the scenario of period decay with a $\Delta$BIC of 14.1. The detected TTV induces a period decay rate ($\dot{P}$) of -1.14$\pm 0.28\times 10^{-8}$ d per day ($-$0.36 s/yr). Fitting the spectral energy distribution, we find infrared excess at the significance level of 1.5 $\sigma$ for WISE W1 and W2 bands, and 2 $\sigma$ level for W3 and W4 bands. This potentially reveals the existence of a stellar disc, consisting of hot dust at 800 $\pm$ 300 K, showing a $L_{\mathrm{ dust}}/L_{\ast }$ of 5 $\pm\ 3\times 10^{-3}$. We obtain a stellar age of 1.0$^{+1.4}_{-0.7}\, \times 10^{9}$ yr from isochrone fitting. The properties of K2-237b potentially serve as a direct observational support to the planet disc migration though more observation are needed.