69 research outputs found
The small and large lags of the elastic and anelastic tides. The virtual identity of two rheophysical theories
The aim of this letter is to discuss the virtual identity of two recent tidal
theories: the creep tide theory of Ferraz-Mello (Cel. Mech. Dyn. Astron. 116,
109, 2013) and the Maxwell model developed by Correia et al. (Astron.
Astrophys. 571, A50, 2014). It includes the discussion of the basic equations
of the theories, which, in both cases, include an elastic and an anelastic
component, and shows that the basic equations of the two theories are
equivalent and differ by only a numerical factor in the anelastic tide. It also
includes a discussion of the lags: the lag of the full tide (geodetic),
dominated by the elastic component, and the phase of the anelastic tide. In
rotating rocky bodies not trapped in a spin-orbit resonance (e.g., the Earth)
the geodetic lag is close to zero and the phase of the semi-diurnal argument in
the anelastic tide is close to 90 degrees. The results obtained from combining
tidal solutions from satellite tracking data and from Topex/Poseidon satellite
altimeter data, by Ray et al., are extended to determine the phase of the
semi-diurnal argument in the Earth's anelastic tide as sigma_0=89.80 \pm 0.05
degrees.Comment: Accepted for publication in Astronomy and Astrophysic
On Tides and Exoplanets
This paper reviews the basic equations used in the study of the tidal
variations of the rotational and orbital elements of a system formed by one
star and one close-in planet as given by the creep tide theory and Darwin's
constant time lag (CTL) theory. At the end, it reviews and discusses the
determinations of the relaxation factors (and time lags) in the case of host
stars and hot Jupiters based on actual observations of orbital decay, stellar
rotation and age, etc. It also includes a recollection of the basic facts
concerning the variations of the rotation of host stars due to the leakage of
angular momentum associated with stellar winds.Comment: 4 figures, IAU Symposium No. 36
Formation and transformation of the 3:1 mean-motion resonance in 55 Cancri System
We report in this paper the numerical simulations of the capture into the 3:1
mean-motion resonance between the planet b and c in the 55 Cancri system. The
results show that this resonance can be obtained by a differential planetary
migration. The moderate initial eccentricities, relatively slower migration and
suitable eccentricity damping rate increase significantly the probability of
being trapped in this resonance. Otherwise, the system crosses the 3:1
commensurability avoiding resonance capture, to be eventually captured into a
2:1 resonance or some other higher-order resonances. After the resonance
capture, the system could jump from one orbital configuration to another one if
the migration continues, making a large region of the configuration space
accessible for a resonance system. These investigations help us understand the
diversity of resonance configurations and put some constrains on the early
dynamical evolution of orbits in the extra-solar planetary systems.Comment: 6 pages with 2 figures. Submitted for publication in the proceedings
of IAU Symposium No.249. A paper telling much more details than this paper is
under preparin
Chirikov diffusion in the asteroidal three-body resonance (5, −2, −2)
The theory of diffusion in many-dimensional Hamiltonian system is applied to asteroidal dynamics. The general formulation developed by Chirikov is applied to the Nesvorný-Morbidelli analytic model of three-body (three-orbit) mean-motion resonances (Jupiter-Saturn-asteroid). In particular, we investigate the diffusion along and across the separatrices of the (5, −2, −2) resonance of the (490) Veritas asteroidal family and their relationship to diffusion in semi-major axis and eccentricity. The estimations of diffusion were obtained using the Melnikov integral, a Hadjidemetriou-type sympletic map and numerical integrations for times up to 108 years.Facultad de Ciencias Astronómicas y GeofÃsicasInstituto de AstrofÃsica de La Plat
Chirikov diffusion in the asteroidal three-body resonance (5, −2, −2)
The theory of diffusion in many-dimensional Hamiltonian system is applied to asteroidal dynamics. The general formulation developed by Chirikov is applied to the Nesvorný-Morbidelli analytic model of three-body (three-orbit) mean-motion resonances (Jupiter-Saturn-asteroid). In particular, we investigate the diffusion along and across the separatrices of the (5, −2, −2) resonance of the (490) Veritas asteroidal family and their relationship to diffusion in semi-major axis and eccentricity. The estimations of diffusion were obtained using the Melnikov integral, a Hadjidemetriou-type sympletic map and numerical integrations for times up to 108 years.Facultad de Ciencias Astronómicas y GeofÃsicasInstituto de AstrofÃsica de La Plat
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