Tidal dissipation in evolving low-mass and solar-type stars with predictions for planetary orbital decay. (arXiv:2008.03262v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Barker_A/0/1/0/all/0/1">Adrian J. Barker</a>
We study tidal dissipation in stars with masses in the range $0.1-1.6
M_odot$ throughout their evolution, including turbulent effective viscosity
acting on equilibrium tides and inertial waves in convection zones, and
internal gravity waves in radiation zones. We consider a range of stellar
evolutionary models and incorporate the frequency-dependent effective viscosity
acting on equilibrium tides based on the latest simulations. We compare the
tidal flow and dissipation obtained with the conventional equilibrium tide,
which is strictly invalid in convection zones, finding that the latter
typically over-predicts the dissipation by a factor of 2-3. Dissipation of
inertial waves is computed using a frequency-averaged formalism accounting for
realistic stellar structure for the first time, and is the dominant mechanism
for binary circularization and synchronization on the main sequence.
Dissipation of gravity waves in the radiation zone assumes these waves to be
fully damped (e.g.~by wave breaking), and is the dominant mechanism for
planetary orbital decay. We calculate the critical planetary mass required for
wave breaking as a function of stellar mass and age, and show that this
mechanism predicts destruction of many hot Jupiters but probably not Earth-mass
planets on the main sequence. We apply our results to compute tidal quality
factors following stellar evolution, and tidal evolutionary timescales, for the
orbital decay of hot Jupiters, and the spin synchronization and circularization
of binary stars. We also provide predictions for shifts in transit arrival
times due to tidally-driven orbital decay of hot Jupiters that may be detected
with NGTS, TESS or PLATO.
We study tidal dissipation in stars with masses in the range $0.1-1.6
M_odot$ throughout their evolution, including turbulent effective viscosity
acting on equilibrium tides and inertial waves in convection zones, and
internal gravity waves in radiation zones. We consider a range of stellar
evolutionary models and incorporate the frequency-dependent effective viscosity
acting on equilibrium tides based on the latest simulations. We compare the
tidal flow and dissipation obtained with the conventional equilibrium tide,
which is strictly invalid in convection zones, finding that the latter
typically over-predicts the dissipation by a factor of 2-3. Dissipation of
inertial waves is computed using a frequency-averaged formalism accounting for
realistic stellar structure for the first time, and is the dominant mechanism
for binary circularization and synchronization on the main sequence.
Dissipation of gravity waves in the radiation zone assumes these waves to be
fully damped (e.g.~by wave breaking), and is the dominant mechanism for
planetary orbital decay. We calculate the critical planetary mass required for
wave breaking as a function of stellar mass and age, and show that this
mechanism predicts destruction of many hot Jupiters but probably not Earth-mass
planets on the main sequence. We apply our results to compute tidal quality
factors following stellar evolution, and tidal evolutionary timescales, for the
orbital decay of hot Jupiters, and the spin synchronization and circularization
of binary stars. We also provide predictions for shifts in transit arrival
times due to tidally-driven orbital decay of hot Jupiters that may be detected
with NGTS, TESS or PLATO.
http://arxiv.org/icons/sfx.gif
