Planet-star interactions with precise transit timing. V. Tidal decay of hot Jupiters through wave breaking

TL;DR

This study models tidal interactions and wave-breaking effects in 550 hot Jupiters to predict orbital decay and identify systems suitable for transit timing observations, revealing that many planets may inspiral within stellar lifetimes.

Contribution

It provides the first comprehensive population-wide analysis of wave-breaking tidal dissipation in hot Jupiters, incorporating stellar uncertainties and predicting observable orbital decay signatures.

Findings

43% of hot Jupiters may inspiral on the main sequence.

Wave breaking is inactive in pre-IAMS stars, affecting tidal dissipation.

Orbital decay signals are likely detectable over multi-decade observations.

Abstract

Tidal interactions shape the evolution of close-in giant planets and internal gravity-wave breaking offers an efficient pathway for dynamical-tide dissipation, although its population-wide impact remains poorly constrained. We aim to quantify wave-breaking tidal dissipation for 550 hot Jupiters, accounting for stellar-parameter uncertainties. We also aim to identify the most promising systems for detecting orbital decay through transit timing.\\ Stellar masses, radii, and ages were homogeneously redetermined from spectroscopic and photometric data using an isochrone fitting. For each system, these parameters were propagated through a dedicated \texttt{MESA} model grid to calculate the tidal quality factor, wave-breaking probability, orbital decay rate, transit-timing diagnostics and destruction timescales.\\ Wave breaking is predicted to be largely inactive in pre-intermediate-age main sequence (pre-IAMS) stars. The tidal quality factor for systems undergoing wave breaking peaks between $10^6$ and $10^7$, consistent with population-level inferences. About 43\% of planets, primarily with periods $\lesssim3.5$~d, are expected to inspiral on the main sequence, providing a physical explanation for the observed tendency of hot Jupiters to orbit younger stars. A further 41\% inspiral during post-main-sequence evolution within the stages considered. Systems with periods $\lesssim 1$~d, which could in principle experience the strongest tidal forcing, are unlikely to trigger wave breaking, leaving planets on stable orbits. Conversely, the most rapidly inspiralling systems with high wave-breaking probability might display measurable orbital-period shortening only over multi-decade baselines, eluding immediate detection. In contrast, the demographic imprint of wave breaking on occurrence rates should emerge more readily, with the first signs already visible in current population statistics.