Doomed Worlds II: Reassessing Suggestions of Orbital Decay for TrES-5 b

TrES-5 b is one of only three ultra-hot Jupiters with suggestions of a possibly decreasing orbital period that have persisted through multiple independent analyses (Maciejewski et al. 2021; Hagey et al. 2022; Ivshina & Winn 2022; Wang et al. 2024; Yeh et al. 2024). While WASP-12 b’s decreasing period is well-explained by tidally induced orbital decay (Patra et al. 2017), and stellar acceleration has been proposed for WASP-4 b (Bouma et al. 2020), the cause of the apparent trend for TrES-5 b has not been satisfactorily explained. This work extends the previous observations by four years with 14 new ground-based transits from 2016-2024 and two newly-published midtimes for data from 2007 and 2009. Four TESS Sectors (75, 77, 82, and 84) have also been included for the first time. With the new data, the case for a decreasing orbital period is much weaker than before. The revised rate of period change, P_dot = 4.2 +- 2.2 ms/yr^-1, is less than half that found in previous work and the preference for a quadratic model over a linear model, as measured through ∆BIC, has been falling since 2020, with a current value of 6. Furthermore, these results are not robust to outliers; removing a single early transit midtime causes the effect to vanish (∆BIC= −1). No other significant periodic signals in the transit timing data are identified. The current data are well explained by a linear ephemeris, implying that there is no orbital decay for TrES-5 b.