Internal wave breaking and the fate of planets around solar-type stars

TL;DR

This paper investigates how internal gravity waves excited by close-in planets influence stellar spin and planetary orbital evolution, emphasizing wave breaking's role in tidal dissipation and planetary survival.

Contribution

It presents numerical simulations showing the amplitude-dependent wave breaking effect on tidal dissipation and its impact on star-planet interactions.

Findings

Wave breaking leads to efficient tidal dissipation.

Reflection without breaking results in minimal dissipation.

Implications for the survival of short-period planets.

Abstract

Internal gravity waves are excited at the interface of convection and radiation zones of a solar-type star by the tidal forcing of a short-period planet. The fate of these waves as they approach the centre of the star depends on their amplitude. We discuss the results of numerical simulations of these waves approaching the centre of a star, and the resulting evolution of the spin of the central regions of the star, and the orbit of the planet. If the waves break, we find efficient tidal dissipation, which is not present if the waves perfectly reflect from the centre. This highlights an important amplitude dependence of the (stellar) tidal quality factor Q', which has implications for the survival of planets on short-period orbits around solar-type stars, with radiative cores.