Chaos in multiplanetary extrasolar systems

Gajdoš, Pavol; Vaňko, M.

doi:10.1093/mnras/stac3200

Cited by 3 publications

(2 citation statements)

References 49 publications

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“…This point is also discussed in a different approach recently by Gajdoš & Vaňko (2023), who found that several observed exoplanetary systems have relatively short Lyapunov times (calculated from the Lyapunov exponent), even down to O(10) yr. This fact implies that the Lyapunov time is not necessarily related to the Lagrange stability of the systems, in good agreement with our finding mentioned above.…”

Section: Introductionmentioning

confidence: 78%

Lagrange versus Lyapunov Stability of Hierarchical Triple Systems: Dependence on the Mutual Inclination between Inner and Outer Orbits

Hayashi

Trani

Suto

2023

ApJ

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While there have been many studies examining the stability of hierarchical triple systems, the meaning of “stability” is somewhat vague and has been interpreted differently in previous literatures. The present paper focuses on “Lagrange stability,” which roughly refers to the stability against the escape of a body from the system, or “disruption” of the triple system, in contrast to “Lyapunov-like stability,” which is related to the chaotic nature of the system dynamics. We compute the evolution of triple systems using direct N-body simulations up to 107 P out, which is significantly longer than previous studies (with P out being the initial orbital period of the outer body). We obtain the resulting disruption timescale T d as a function of the triple orbital parameters with particular attention to the dependence on the mutual inclination between the inner and outer orbits, i mut. By doing so, we have clarified explicitly the difference between Lagrange and Lyapunov stabilities in astronomical triples. Furthermore, we find that the von Zeipel–Kozai–Lidov oscillations significantly destabilize inclined triples (roughly with 60° < i mut < 150°) relative to those with i mut = 0°. On the other hand, retrograde triples with i mut > 160° become strongly stabilized with much longer disruption timescales. We show the sensitivity of the normalized disruption timescale T d/P out to the orbital parameters of triple system. The resulting T d/P out distribution is practically more useful in a broad range of astronomical applications than the stability criterion based on the Lyapunov divergence.

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Section: Introductionmentioning

confidence: 78%

Lagrange versus Lyapunov Stability of Hierarchical Triple Systems: Dependence on the Mutual Inclination between Inner and Outer Orbits

Hayashi

Trani

Suto

2023

ApJ

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“…The original resonant architecture was then broken during a later phase of dynamical instability. This scenario is supported by dynamical population studies of exoplanetary systems (Laskar & Petit 2017;Gajdoš & Vaňko 2023) revealing how 25-45% of known multiplanet systems, and the majority of high-multiplicity systems hosting four or more planets like V1298 Tau, show the signatures of chaos and instability in their architectures. We investigate the plausible causes of the instability in Sects.…”

Section: Dynamical Excitation Of V1298 Tau B and Ementioning

confidence: 89%

The GAPS programme at TNG

Turrini,

Marzari,

Polychroni

et al. 2023

A&A

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Context. Observational data from space- and ground-based campaigns have revealed that the 10-30 Ma old V1298Tau star hosts a compact and massive system of four planets. Mass estimates are available for the two outer giant planets and point to unexpectedly high densities for their young ages. Aims. We investigate the formation of these two outermost giant planets, V1298 Tau b and e, and the present dynamical state of V1298 Tau’s global architecture in order to shed light on the history of this young and peculiar extrasolar system. Methods. We performed detailed N-body simulations to explore the link between the densities of V1298 Tau b and e and their migration and accretion of planetesimals within the native circumstellar disk. We combined N-body simulations and the normalized angular momentum deficit (NAMD) analysis of the architecture to characterize V1298 Tau’s dynamical state and connect it to the formation history of the system. We searched for outer planetary companions to constrain V1298 Tau’s planetary architecture and the extension of its primordial circumstellar disk. Results. The high densities of V1298 Tau b and e suggest they formed at quite a distance from their host star, likely beyond the CO2 snowline. The higher nominal density of V1298 Tau e suggests it formed farther out than V1298 Tau b. The current architecture of V1298 Tau is not characterized by resonant chains. Planet-planet scattering with an outer giant planet is the most likely cause for the lack of a resonant chain between V1298 Tau’s planets, but currently our search for outer companions using SPHERE and Gaia observations can exclude only the presence of planets more massive than 2 MJ. Conclusions. The most plausible scenario for V1298 Tau’s formation is that the system formed by convergent migration and resonant trapping of planets born in a compact and plausibly massive disk. In the wake of their migration, V1298 Tau b and e would have left a dynamically excited protoplanetary disk, naturally creating the conditions for the later breaking of the resonant chain by planet-planet scattering.

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Estimation of the diffusion time in a triaxial galactic potential

Cincotta,

Giordano

2023

Monthly Notices of the Royal Astronomical Society

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In this work we apply the Shannon entropy based method to derive a diffusion or instability time in a triaxial model resembling an elliptical galaxy. We succeed in getting an accurate time-scale for diffusion using this novel technique after adopting a particular initial starting space, the one defined by the unperturbed integrals of the system. Comparisons with other standard techniques, such as a least squares fit on the variance evolution of the integrals and the straight numerical integrations of the equations of motion, are included. The physical results provided in this effort reveal that the role of chaotic motion in triaxial galactic models is almost irrelevant in galactic time-scales, in agreement with previous qualitative approaches to this issue.

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Chaos in multiplanetary extrasolar systems

Cited by 3 publications

References 49 publications

Lagrange versus Lyapunov Stability of Hierarchical Triple Systems: Dependence on the Mutual Inclination between Inner and Outer Orbits

Lagrange versus Lyapunov Stability of Hierarchical Triple Systems: Dependence on the Mutual Inclination between Inner and Outer Orbits

The GAPS programme at TNG

Estimation of the diffusion time in a triaxial galactic potential

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