Chasing the Tides: Searching for Orbital Decay Signatures in Transit Timing Data and Tidal Models for 20 Hot Jupiters

TL;DR

This study analyzes transit timing variations for 20 hot Jupiters, identifying orbital decay in three cases and comparing observed decay rates with tidal models, providing insights into tidal dissipation processes.

Contribution

It offers the first comprehensive transit timing analysis for these systems, updating decay rates and testing tidal models against observational data.

Findings

WASP-12 b shows a measurable orbital decay rate.

TrES-1 b's decay rate does not match theoretical predictions.

WASP-121 b exhibits orbital growth consistent with tidal theories.

Abstract

In this work, we present a transit timing variation analysis for 20 hot Jupiter systems, which we interpret with theoretical tidal dissipation models. For the majority of the sample, we conclude that a constant orbital period model represents the timing data best. Only WASP-12 b, TrES-1 b and WASP-121 b exhibit a changing orbital period, according to the most up-to-date results. We updated the orbital decay rate of WASP-12 b to $\dot{P} = -29.4 \pm 4.0 \mathrm{~ms~yr^{-1}}$ and the corresponding stellar tidal quality factor to $Q_*^{\prime} = 1.72 \pm 0.18 \times 10^5$. For TrES-1 b, the median quadratic model suggests a period decrease at a rate of $-14.9 \pm 0.6 \mathrm{~ms~yr^{-1}}$, but the corresponding $Q_*^{\prime} = 570 \pm 60$ does not agree with the theoretical estimates, which suggest $Q_*^{\prime} \sim 10^6$ due to internal gravity wave dissipation. Lastly, WASP-121 b exhibits orbital growth at a rate of $15.1 \pm 0.8 \mathrm{~ms~yr^{-1}}$, and theoretical results support outward migration due to strong inertial wave dissipation.