scholarly journals Constraining planetary migration and tidal dissipation with coeval hot Jupiters

2018 ◽  
Vol 477 (1) ◽  
pp. 175-189 ◽  
Author(s):  
Christopher E O'Connor ◽  
Bradley M S Hansen
Keyword(s):  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Planetary Migration

scholarly journals Constraining Planetary Migration Mechanisms in Systems of Giant Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 386-390
Author(s):  
Rebekah I. Dawson ◽  
Ruth A. Murray-Clay ◽  
John Asher Johnson
Keyword(s):  
Giant Planet ◽  
Giant Planets ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Short Period ◽  
Pile Up ◽  
Planetary Migration ◽  
Multi Body ◽  
Host Stars

AbstractIt was once widely believed that planets formed peacefully in situ in their proto-planetary disks and subsequently remain in place. Instead, growing evidence suggests that many giant planets undergo dynamical rearrangement that results in planets migrating inward in the disk, far from their birthplaces. However, it remains debated whether this migration is caused by smooth planet-disk interactions or violent multi-body interactions. Both classes of model can produce Jupiter-mass planets orbiting within 0.1 AU of their host stars, also known as hot Jupiters. In the latter class of model, another planet or star in the system perturbs the Jupiter onto a highly eccentric orbit, which tidal dissipation subsequently shrinks and circularizes during close passages to the star. We assess the prevalence of smooth vs. violent migration through two studies. First, motivated by the predictions of Socrates et al. (2012), we search for super-eccentric hot Jupiter progenitors by using the “photoeccentric effect” to measure the eccentricities of Kepler giant planet candidates from their transit light curves. We find a significant lack of super- eccentric proto-hot Jupiters compared to the number expected, allowing us to place an upper limit on the fraction of hot Jupiters created by stellar binaries. Second, if both planet-disk and multi-body interactions commonly cause giant planet migration, physical properties of the proto-planetary environment may determine which is triggered. We identify three trends in which giant planets orbiting metal rich stars show signatures of planet-planet interactions: (1) gas giants orbiting within 1 AU of metal-rich stars have a range of eccentricities, whereas those orbiting metal- poor stars are restricted to lower eccentricities; (2) metal-rich stars host most eccentric proto-hot Jupiters undergoing tidal circularization; and (3) the pile-up of short-period giant planets, missing in the Kepler sample, is a feature of metal-rich stars and is largely recovered for giants orbiting metal-rich Kepler host stars. These two studies suggest that both disk migration and planet-planet interactions may be widespread, with the latter occurring primarily in metal-rich planetary systems where multiple giant planets can form. Funded by NSF-GRFP DGE-1144152.

scholarly journals The ominous fate of exomoons around hot Jupiters in the high-eccentricity migration scenario

2020 ◽  
Vol 499 (3) ◽  
pp. 4195-4205
Author(s):  
Alessandro A Trani ◽  
Adrian S Hamers ◽  
Aaron Geller ◽  
Mario Spera
Keyword(s):  
Migration Process ◽  
High Eccentricity ◽  
Primary Star ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Tidal Interactions ◽  
Extrasolar Systems ◽  
Natural Satellites ◽  
Planetary Migration ◽  
Host Stars

ABSTRACT All the giant planets in the Solar system host a large number of natural satellites. Moons in extrasolar systems are difficult to detect, but a Neptune-sized exomoon candidate has been recently found around a Jupiter-sized planet in the Kepler-1625b system. Due to their relative ease of detection, hot Jupiters (HJs), which reside in close orbits around their host stars with a period of a few days, may be very good candidates to search for exomoons. It is still unknown whether the HJ population can host (or may have hosted) exomoons. One suggested formation channel for HJs is high-eccentricity migration induced by a stellar binary companion combined with tidal dissipation. Here, we investigate under which circumstances an exomoon can prevent or allow high-eccentricity migration of a HJ, and in the latter case, if the exomoon can survive the migration process. We use both semi-analytic arguments, as well as direct N-body simulations including tidal interactions. Our results show that massive exomoons are efficient at preventing high-eccentricity migration. If an exomoon does instead allow for planetary migration, it is unlikely that the HJ formed can host exomoons since the moon will either spiral on to the planet or escape from it during the migration process. A few escaped exomoons can become stable planets after the Jupiter has migrated, or by tidally migrating themselves. The majority of the exomoons end up being ejected from the system or colliding with the primary star and the host planet. Such collisions might none the less leave observable features, such as a debris disc around the primary star or exorings around the close-in giant.

scholarly journals Tidal dissipation within hot Jupiters: a new appraisal

2006 ◽  
Vol 462 (1) ◽  
pp. L5-L8 ◽  
Author(s):  
B. Levrard ◽  
A. C. M. Correia ◽  
G. Chabrier ◽  
I. Baraffe ◽  
F. Selsis ◽  
...  
Keyword(s):  
Tidal Dissipation ◽  
Hot Jupiters

Tidal dissipation modelling in gaseous giant planets at the time of space missions

2021 ◽  
Author(s):  
Hachem Dhouib ◽  
Stéphane Mathis ◽  
Florian Debras ◽  
Aurélie Astoul ◽  
Clément Baruteau
Keyword(s):  
Internal Structure ◽  
Differential Rotation ◽  
Giant Planets ◽  
Solid Core ◽  
Large Radius ◽  
Mixing Zone ◽  
Convective Envelope ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Tidal Waves

<p>Gaseous giant planets (Jupiter and Saturn in our solar system and hot Jupiters around other stars) are turbulent rotating magnetic objects that have strong and complex interactions with their environment (their moons in the case of Jupiter and Saturn and their host stars in the case of hot Jupiters/Saturns). In such systems, the dissipation of tidal waves excited by tidal forces shape the orbital architecture and the rotational dynamics of the planets.</p> <p>During the last decade, a revolution has occurred for our understanding of tides in these systems. First, Lainey et al. (2009, 2012, 2017) have measured tidal dissipation stronger by one order of magnitude than expected in Jupiter and Saturn. Second, unexplained broad diversity of orbital architectures and large radius of some hot Jupiters are observed in exoplanetary systems. Finally, new constraints obtained thanks to <em>Kepler</em>/K2 and TESS indicate that tidal dissipation in gaseous giant exoplanets is weaker than in Jupiter and in Saturn (Ogilvie 2014, Van Eylen et al. 2018, Huber et al. 2019).</p> <p>Furthermore, the space mission JUNO and the grand finale of the CASSINI mission have revolutionized our knowledge of the interiors of giant planets. We now know, for example, that Jupiter is a very complex planet: it is a stratified planet with, from the surface to the core, a differentially rotating convective envelope, a first mixing zone (with stratified convection), a uniformly rotating magnetised convective zone, a second magnetized mixing zone (the diluted core, potentially in stratified convection) and a solid core (Debras & Chabrier 2019). So far, tides in these planets have been studied by assuming a simplified internal structure with a stable rocky and icy core (Remus et al. 2012, 2015) and a deep convective envelope surrounded by a thin stable atmosphere (Ogilvie & Lin 2004) where mixing processes, differential rotation and magnetic field were completely neglected.</p> <p>Our objective is thus to predict tidal dissipation using internal structure models, which agree with these last observational constrains. In this work, we build a new ab-initio model of tidal dissipation in giant planets that coherently takes into account the interactions of tidal waves with their complex stratification induced by the mixing of heavy elements, their zonal winds, and (dynamo) magnetic fields. This model is a semi-global model in the planetary equatorial plane. We study the linear excitation of tidal magneto-gravito-inertial progressive waves and standing modes. We take into account the buoyancy, the compressibility, the Coriolis acceleration (including differential rotation), and the Lorentz force. The tidal waves are submitted to the different potential dissipative processes: Ohmic, thermal, molecular diffusivities, and viscosity. We here present the general formalism and the potential regimes of parameters that should be explored. The quantities of interest such as tidal torque, dissipation, and heating are derived. This will pave the way for full 3D numerical simulations that will take into account complex internal structure and dynamics of gaseous giant (exo-)planets in spherical/spheroidal geometry.</p> <p> </p>

scholarly journals Layered semi-convection and tides in giant planet interiors

2019 ◽  
Vol 626 ◽  
pp. A82 ◽  
Author(s):  
Q. André ◽  
S. Mathis ◽  
A. J. Barker
Keyword(s):  
Large Fraction ◽  
Giant Planet ◽  
Vertical Direction ◽  
Thermal Dissipation ◽  
Free Boundaries ◽  
Compositional Gradient ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Tidal Waves ◽  
Dissipation Rates

Context. Recent Juno observations have suggested that the heavy elements in Jupiter could be diluted throughout a large fraction of its gaseous envelope, providing a stabilising compositional gradient over an extended region of the planet. This could trigger layered semi-convection, which, in the context of giant planets more generally, may explain Saturn’s luminosity excess and play a role in causing the abnormally large radii of some hot Jupiters. In giant planet interiors, it could take the form of density staircases, which are convective layers separated by thin stably stratified interfaces. In addition, the efficiency of tidal dissipation is known to depend strongly on the planetary internal structure. Aims. We aim to study the resulting tidal dissipation when internal waves are excited in a region of layered semi-convection by tidal gravitational forcing due to other bodies (such as moons in giant planet systems, or stars in hot Jupiter systems). Methods. We adopt a local Cartesian model with a background layered density profile subjected to an imposed tidal forcing, and we compute the viscous and thermal dissipation rates numerically. We consider two sets of boundary conditions in the vertical direction: periodic boundaries and impenetrable, stress-free boundaries, with periodic conditions in the horizontal directions in each case. These models are appropriate for studying the forcing of short-wavelength tidal waves in part of a region of layered semi-convection, and in an extended envelope containing layered semi-convection, respectively. Results. We find that the rates of tidal dissipation can be enhanced in a region of layered semi-convection compared to a uniformly convective medium, where the latter corresponds with the usual assumption adopted in giant planet interior models. In particular, a region of layered semi-convection possesses a richer set of resonances, allowing enhanced dissipation for a wider range of tidal frequencies. The details of these results significantly depend on the structural properties of the layered semi-convective regions. Conclusions. Layered semi-convection could contribute towards explaining the high tidal dissipation rates observed in Jupiter and Saturn, which have not yet been fully explained by theory. Further work is required to explore the efficiency of this mechanism in global models.

scholarly journals On the equilibrium rotation of Hot Jupiters in eccentric and excited orbits

2010 ◽  
Vol 6 (S276) ◽  
pp. 287-294
Author(s):  
Alexandre C. M. Correia
Keyword(s):  
Solar System ◽  
Rotation Rate ◽  
Tidal Effects ◽  
Tidal Dissipation ◽  
Continuous Action ◽  
Hot Jupiters ◽  
Synchronous Motion ◽  
Eccentric Orbits ◽  
Synchronous Rotation ◽  
Probable Outcome

AbstractHot-Jupiters are a common sub-class of exoplanets, which are enough close to the star to undergo tidal dissipation. The continuous action of tides modify the rotation of the planets until an equilibrium situation is reached. It is often assumed that synchronous motion is the most probable outcome of tidal evolution, since synchronous rotation is observed for the majority of the satellites in the Solar System. This is true for circular orbits, but when the orbits are eccentric, tidal effects are stronger when the planets are closer to the star, and therefore, the rotation rate tends to equalize the orbital speed rate at the pericenter (which is faster than synchronous rotation). An additional complication arises if the eccentricity is not constant and undergoes periodic perturbations from an external companion. Here we obtain an expression for the equilibrium rotation of Hot-Jupiters undergoing tidal dissipation and planetary perturbations. We show that for these planets, the equilibrium rotation rate is faster than for non-perturbed eccentric orbits.

scholarly journals Tidal dissipation in evolving low-mass and solar-type stars with predictions for planetary orbital decay

2020 ◽  
Vol 498 (2) ◽  
pp. 2270-2294
Author(s):  
A J Barker
Keyword(s):  
Gravity Waves ◽  
Wave Breaking ◽  
Effective Viscosity ◽  
Main Sequence ◽  
Internal Gravity Waves ◽  
Stellar Structure ◽  
Tidal Dissipation ◽  
Dominant Mechanism ◽  
Hot Jupiters ◽  
Orbital Decay

ABSTRACT We study tidal dissipation in stars with masses in the range 0.1–1.6 M⊙ throughout their evolution, including turbulent effective viscosity acting on equilibrium tides and inertial waves (IWs) 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 overpredicts the dissipation by a factor of 2–3. Dissipation of IWs 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 time-scales, 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.

scholarly journals Three short-period Jupiters from TESS

2020 ◽  
Vol 639 ◽  
pp. A76 ◽  
Author(s):  
L. D. Nielsen ◽  
R. Brahm ◽  
F. Bouchy ◽  
N. Espinoza ◽  
O. Turner ◽  
...  
Keyword(s):  
Stellar System ◽  
Phase Curve ◽  
Mass Determination ◽  
Tidal Dissipation ◽  
Giant Star ◽  
Hot Jupiters ◽  
Short Period ◽  
Host Stars ◽  
Interesting System

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.

scholarly journals Nonlinear tidal flows in short-period planets

2019 ◽  
Vol 82 ◽  
pp. 43-50
Author(s):  
A.J. Barker
Keyword(s):  
Extrasolar Planets ◽  
Spin Orbit ◽  
Tidal Evolution ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Fluid Instability ◽  
Short Period ◽  
Elliptical Instability ◽  
Turbulent Damping ◽  
Tidal Deformations

I discuss two related nonlinear mechanisms of tidal dissipation that require finite tidal deformations for their operation: the elliptical instability and the precessional instability. Both are likely to be important for the tidal evolution of short-period extrasolar planets. The elliptical instability is a fluid instability of elliptical streamlines, such as in tidally deformed non-synchronously rotating or non-circularly orbiting planets. I summarise the results of local and global simulations that indicate this mechanism to be important for tidal spin synchronisation, planetary spin-orbit alignment and orbital circularisation for the shortest period hot Jupiters. The precessional instability is a fluid instability that occurs in planets undergoing axial precession, such as those with spin-orbit misalignments (non-zero obliquities). I summarise the outcome of local MHD simulations designed to study the turbulent damping of axial precession, which suggest this mechanism to be important in driving tidal evolution of the spin-orbit angle for hot Jupiters. Avenues for future work are also discussed.

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