Planet-star interactions with precise transit timing

V. Tidal decay of hot Jupiters through wave breaking

Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland

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Received: 12 December 2025
Accepted: 16 February 2026

Abstract

Aims. 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.

Methods. 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 MESA model grid to calculate the tidal quality factor, wave-breaking probability, orbital decay rate, and transit-timing diagnostics. The long-term orbital evolution was modelled to predict planetary destruction timescales.

Results. Wave breaking is predicted to be largely inactive in pre-intermediate-age main sequence (pre-IAMS) stars. For hosts with masses ≲1.2 M_⊙, it becomes effective after the IAMS, while in more massive stars, it begins between the IAMS and the terminal-age main sequence (TAMS). The tidal quality factor for systems undergoing wave breaking peaks between 10⁶ and 10⁷, consistent with population-level inferences. About 43% of planets, primarily with periods ≲3.5 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 postmain-sequence evolution within the stages considered. Roche-limit disruption dominates overall, with engulfment occurring mainly for planets with periods ≳5-6 d. Systems with periods ≲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.