Tidal migration of exoplanets around M-dwarfs: frequency-dependent tidal dissipation

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Auteurs principaux: Wu, Samantha C., Dewberry, Janosz W., Fuller, Jim
Format: Preprint
Publié: 2023
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author Wu, Samantha C.
Dewberry, Janosz W.
Fuller, Jim
author_facet Wu, Samantha C.
Dewberry, Janosz W.
Fuller, Jim
contents The orbital architectures of short-period exoplanet systems are shaped by tidal dissipation in their host stars. For low-mass M-dwarfs whose dynamical tidal response comprises a dense spectrum of inertial modes at low frequencies, resolving the frequency dependence of tidal dissipation is crucial to capturing the effect of tides on planetary orbits throughout the evolutionary stages of the host star. We use non-perturbative spectral methods to calculate the normal mode oscillations of a fully-convective M-dwarf modeled using realistic stellar profiles from MESA. We compute the dissipative tidal response composed of contributions from each mode as well as non-adiabatic coupling between the modes, which we find to be an essential component of the dissipative calculations. Using our results for dissipation, we then compute of the evolution of circular, coplanar planetary orbits under the influence of tides in the host star. We find that orbital migration driven by resonance locking affects the orbits of Earth-mass planets at orbital periods $P_{\rm orb} \lesssim 1.5$ day and of Jupiter-mass planets at $P_{\rm orb} \lesssim 2.5$ day. Due to resonantly-driven orbital decay and outward migration, we predict a dearth of small planets closer than $P_{\rm orb} \sim 1$ day and similarly sparse numbers of more massive planets out to $P_{\rm orb} \sim 3$ day.
format Preprint
id arxiv_https___arxiv_org_abs_2310_04588
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Tidal migration of exoplanets around M-dwarfs: frequency-dependent tidal dissipation
Wu, Samantha C.
Dewberry, Janosz W.
Fuller, Jim
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
The orbital architectures of short-period exoplanet systems are shaped by tidal dissipation in their host stars. For low-mass M-dwarfs whose dynamical tidal response comprises a dense spectrum of inertial modes at low frequencies, resolving the frequency dependence of tidal dissipation is crucial to capturing the effect of tides on planetary orbits throughout the evolutionary stages of the host star. We use non-perturbative spectral methods to calculate the normal mode oscillations of a fully-convective M-dwarf modeled using realistic stellar profiles from MESA. We compute the dissipative tidal response composed of contributions from each mode as well as non-adiabatic coupling between the modes, which we find to be an essential component of the dissipative calculations. Using our results for dissipation, we then compute of the evolution of circular, coplanar planetary orbits under the influence of tides in the host star. We find that orbital migration driven by resonance locking affects the orbits of Earth-mass planets at orbital periods $P_{\rm orb} \lesssim 1.5$ day and of Jupiter-mass planets at $P_{\rm orb} \lesssim 2.5$ day. Due to resonantly-driven orbital decay and outward migration, we predict a dearth of small planets closer than $P_{\rm orb} \sim 1$ day and similarly sparse numbers of more massive planets out to $P_{\rm orb} \sim 3$ day.
title Tidal migration of exoplanets around M-dwarfs: frequency-dependent tidal dissipation
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2310.04588