TOI-3362b: A Proto Hot Jupiter Undergoing High-eccentricity Tidal Migration

Hot Jupiters were the first exoplanets to be discovered around main sequence stars and astonished us with their close-in orbits. They are a prime example of how exoplanets have challenged our textbook, solar-system inspired story of how planetary systems form and evolve. More than twenty years after the discovery of the first hot Jupiter, there is no consensus on their predominant origin channel. Three classes of hot Jupiter creation hypotheses have been proposed: in situ formation, disk migration, and high-eccentricity tidal migration. Although no origin channel alone satisfactorily explains all the evidence, two major origin channels together plausibly account for properties of hot Jupiters themselves and their connections to other exoplanet populations.

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Formation of hot Jupiters through secular chaos and dynamical tides

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1011 ◽

2019 ◽

Vol 486 (2) ◽

pp. 2265-2280 ◽

Cited By ~ 5

Author(s):

Jean Teyssandier ◽

Dong Lai ◽

Michelle Vick

Keyword(s):

Semimajor Axis ◽

Giant Planet ◽

Giant Planets ◽

Orbital Energy ◽

High Eccentricity ◽

Hot Jupiters ◽

Orbital Decay ◽

Short Period ◽

Orbital Periods ◽

Hot Jupiter

Abstract The population of giant planets on short-period orbits can potentially be explained by some flavours of high-eccentricity migration. In this paper, we investigate one such mechanism involving ‘secular chaos’, in which secular interactions between at least three giant planets push the inner planet to a highly eccentric orbit, followed by tidal circularization and orbital decay. In addition to the equilibrium tidal friction, we incorporate dissipation due to dynamical tides that are excited inside the giant planet. Using the method of Gaussian rings to account for planet–planet interactions, we explore the conditions for extreme eccentricity excitation via secular chaos and the properties of hot Jupiters formed in this migration channel. Our calculations show that once the inner planet reaches a sufficiently large eccentricity, dynamical tides quickly dissipate the orbital energy, producing an eccentric warm Jupiter, which then decays in semimajor axis through equilibrium tides to become a hot Jupiter. Dynamical tides help the planet avoid tidal disruption, increasing the chance of forming a hot Jupiter, although not all planets survive the process. We find that the final orbital periods generally lie in the range of 2–3 d, somewhat shorter than those of the observed hot Jupiter population. We couple the planet migration to the stellar spin evolution to predict the final spin-orbit misalignments. The distribution of the misalignment angles we obtain shows a lack of retrograde orbits compared to observations. Our results suggest that high-eccentricity migration via secular chaos can only account for a fraction of the observed hot Jupiter population.

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Observable Predictions from Perturber-coupled High-eccentricity Tidal Migration of Warm Jupiters

The Astronomical Journal ◽

10.3847/1538-3881/abe61f ◽

2021 ◽

Vol 161 (4) ◽

pp. 200

Author(s):

Jonathan M. Jackson ◽

Rebekah I. Dawson ◽

Andrew Shannon ◽

Cristobal Petrovich

Keyword(s):

High Eccentricity ◽

Tidal Migration

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Constraining the orbit of the planet-hosting binary τ Boötis

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834368 ◽

2019 ◽

Vol 625 ◽

pp. A59 ◽

Cited By ~ 2

Author(s):

A. B. Justesen ◽

S. Albrecht

Keyword(s):

High Eccentricity ◽

Primary Star ◽

Orbital Inclination ◽

Hot Jupiters ◽

Migration History ◽

History Of ◽

And Migration ◽

Planetary Migration ◽

Astrometric Data ◽

Hot Jupiter

Context. The formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter τ Boo Ab orbits the primary star in the long-period (P ≳ 1000 yr), highly eccentric (e ~ 0.9) double star system τ Boötis. Due to the long orbital period, the orbit of the stellar binary is poorly constrained. Aims. Here we aim to constrain the orbit of the stellar binary τ Boo AB in order to investigate the formation and migration history of the system. The mutual orbital inclination of the stellar companion and the hot Jupiter has important implications for planet migration. The binary eccentricity and periastron distance are important for understanding the conditions under which τ Boo Ab formed. Methods. We combine more than 150 yr of astrometric data with twenty-five years of high-precision radial velocities. The combination of sky-projected and line-of-sight measurements places tight constraints on the orbital inclination, eccentricity, and periastron distance of τ Boo AB. Results. We determine the orbit of τ Boo B and find an orbital inclination of 47.2−3.7+2.7°, a periastron distance of 28.3−3.0+2.3 au, and an eccentricity of 0.87−0.03+0.04. We find that the orbital inclinations of τ Boo Ab and τ Boo B, as well as the stellar spin-axis of τ Boo A coincide at ~45°, a result consistent with the assumption of a well-aligned, coplanar system. Conclusions. The likely aligned, coplanar configuration suggests planetary migration within a well-aligned protoplanetary disc. Due to the high eccentricity and small periastron distance of τ Boo B, the protoplanetary disc was tidally truncated at ≈6 au. We suggest that τ Boo Ab formed near the edge of the truncated disc and migrated inwards with high eccentricity due to spiral waves generated by the stellar companion.

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Probing Signatures of a Distant Planet around the Young T-Tauri Star CI Tau Hosting a Possible Hot Jupiter

The Astrophysical Journal ◽

10.3847/2041-8213/aac6d2 ◽

2018 ◽

Vol 859 (2) ◽

pp. L28 ◽

Cited By ~ 2

Author(s):

Mihoko Konishi ◽

Jun Hashimoto ◽

Yasunori Hori

Keyword(s):

Tauri Star ◽

T Tauri ◽

Hot Jupiter

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Numerical Investigation on the Leakage and Static Stability Characteristics of Pocket Damper Seals at High Eccentricity Ratios

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4038081 ◽

2017 ◽

Vol 140 (4) ◽

Cited By ~ 2

Author(s):

Zhigang Li ◽

Jun Li ◽

Zhenping Feng

Keyword(s):

Static Stability ◽

Operating Conditions ◽

Eccentricity Ratio ◽

Static Stiffness ◽

Flow Conditions ◽

Experiment Data ◽

High Eccentricity ◽

Stiffness Coefficients ◽

Direct Stiffness ◽

Gas Seals

Annular gas seals for compressors and turbines are designed to operate in a nominally centered position in which the rotor and stator are at concentric condition, but due to the rotor–stator misalignment or flexible rotor deflection, many seals usually are suffering from high eccentricity. The centering force (represented by static stiffness) of an annular gas seal at eccentricity plays a pronounced effect on the rotordynamic and static stability behavior of rotating machines. The paper deals with the leakage and static stability behavior of a fully partitioned pocket damper seal (FPDS) at high eccentricity ratios. The present work introduces a novel mesh generation method for the full 360 deg mesh of annular gas seals with eccentric rotor, based on the mesh deformation technique. The leakage flow rates, static fluid-induced response forces, and static stiffness coefficients were solved for the FPDS at high eccentricity ratios, using the steady Reynolds-averaged Navier–Stokes solution approach. The calculations were performed at typical operating conditions including seven rotor eccentricity ratios up to 0.9 for four rotational speeds (0 rpm, 7000 rpm, 11,000 rpm, and 15,000 rpm) including the nonrotating condition, three pressure ratios (0.17, 0.35, and 0.50) including the choked exit flow condition, two inlet preswirl velocities (0 m/s, 60 m/s). The numerical method was validated by comparisons to the experiment data of static stiffness coefficients at choked exit flow conditions. The static direct and cross-coupling stiffness coefficients are in reasonable agreement with the experiment data. An interesting observation stemming from these numerical results is that the FPDS has a positive direct stiffness as long as it operates at subsonic exit flow conditions; no matter the eccentricity ratio and rotational speed are high or low. For the choked exit condition, the FPDS shows negative direct stiffness at low eccentricity ratio and then crosses over to positive value at the crossover eccentricity ratio (0.5–0.7) following a trend indicative of a parabola. Therefore, the negative static direct stiffness is limited to the specific operating conditions: choked exit flow condition and low eccentricity ratio less than the crossover eccentricity ratio, where the pocket damper seal (PDS) would be statically unstable.

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