The random component of planetary rotation

Lissauer, Jack J.; Safronov, V. S.

doi:10.1016/0019-1035(91)90213-d

Cited by 55 publications

(43 citation statements)

References 25 publications

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“…Six of our planets have spin vectors aligned with the common orbital vector, while the remaining three (Venus, Uranus, and Pluto) are retrograde. Direct simulations can track the spin vectors of planetesimals to determine the trends in obliquity and distinguish between models where planets are gradually spun up versus those where a massive late-stage impact dominates (Lissauer and Safronov 1991, Dones and Tremaine 1993, Greenberg et al 1996. This issue is related to the likelihood of creating Earth's Moon with a large impact (Cameron andBenz 1991, Ida et al 1997).…”

Section: Outstanding Issues In Planet Formationmentioning

confidence: 99%

Direct Large-Scale N-Body Simulations of Planetesimal Dynamics

Richardson

Quinn

Stadel

et al. 2000

Icarus

229

210

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We describe a new direct numerical method for simulating planetesimal dynamics in which N ∼ 10 6 or more bodies can be evolved simultaneously in three spatial dimensions over hundreds of dynamical times. This represents several orders of magnitude improvement in resolution over previous studies. The advance is made possible through modification of a stable and tested cosmological code optimized for massively parallel computers. However, owing to the excellent scalability and portability of the code, modest clusters of workstations can treat problems with N ∼ 10 5 particles in a practical fashion.The code features algorithms for detection and resolution of collisions and takes into account the strong central force field and flattened Keplerian disk geometry of planetesimal systems. We demonstrate the range of problems that can be addressed by presenting simulations that illustrate oligarchic growth of protoplanets, planet formation in the presence of giant planet perturbations, the formation of the jovian moons, and orbital migration via planetesimal scattering. We also describe methods under development for increasing the timescale of the simulations by several orders of magnitude.

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Section: Outstanding Issues In Planet Formationmentioning

confidence: 99%

Direct Large-Scale N-Body Simulations of Planetesimal Dynamics

Richardson

Quinn

Stadel

et al. 2000

Icarus

229

210

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“…Recently, though, opinion has shifted to the idea that late, large impacts play a dominant role in establishing the spins of the terrestrial planets (Hartmann & Vail 1986 ;Lissauer & Safronov 1991 ;Dones & Tremaine 1993 ;Lissauer 1995). The spin that results from numerous large impacts may be either prograde or retrograde.…”

Section: Speculations Concerning Venusmentioning

confidence: 99%

Nonlinear Core-Mantle Coupling

Touma

Wisdom

2001

The Astronomical Journal

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We explore the nonlinear dynamics of a forced core-mantle system. We show that the free axisymmetric motion of a uniform-vorticity Ñuid core coupled to a rigid mantle (the model) is Poincare-Hough integrable. We derive an approximate Hamiltonian for the core tilt mode that includes the leading nonlinear contribution. We then include gravitational perturbations in the analysis. We identify the principal nonlinear prograde and retrograde resonances and the characteristic excitation associated with each. We compare the nonlinear excitation with the excitation expected in the corresponding linear model. The nonlinear model indicates that for each principal commensurability there are multiple overlapping resonances, and so varying degrees of chaotic behavior are predicted. Chaotic behavior at the principal coremantle commensurabilities is conÐrmed with surfaces of section. We then present the results of numerical evolutions done with a generalization of our (1994) Lie-Poisson integrator to allow for a Poincarecore, core-mantle friction, and tidal dissipation. We use our analytical and numerical models to Hough explore the evolution of Earth through the prograde core-mantle resonances and to explore the evolution of Venus through the retrograde resonances. Heating of the core-mantle boundary during resonance passage is much greater for Venus than for Earth. We raise the question whether heating during coremantle resonance passage could be responsible for the global resurfacing of Venus.

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“…How does the primordial surface density alter the evolution? What fixes the spin orientation and period of the planets-uniform spin-up from planetesimal accretion [64], or a stochastic process dominated by the very last giant collisions [65]? Is it feasible that the earth suffered a giant impact late in its growth that led to the formation of the moon [29]?…”

Section: Cosmology Meets Cosmogony: Planetary System Formationmentioning

confidence: 99%