arXiv subjects

Demétrio Tadeu Ceccatto

Publications and source records attributed to Demétrio Tadeu Ceccatto.

3 recordsLinked to original sources

arXiv2026

Revisiting the dynamics of the Prometheus-Pandora system

This study revisits the dynamics of Prometheus and Pandora. The analysis focuses on their current orbits and considers mutual perturbations and the non-spherical shape of Saturn. Numerical integrations of the full equations of motion were performed in the context of the N-body problem using a dense set of initial conditions. Spectral analysis of these orbits, together with an interpretation of the dynamical maps, revealed several resonance domains of various orders between Prometheus and Pandora, including the 121:118 resonance domain. Resolving the secular equations for eccentricity and inclination revealed the absence of a forced component in both cases. The period associated with the precession rate, $Δ\varpi$, corresponds to the anti-alignment period. Chaos was quantified by analysing the diffusion of independent frequencies, which indicates dynamics governed by weak chaos. Minor perturbations caused by the Janus-Epimetheus pair on the orbits of Prometheus and Pandora were also considered. Finally, we investigated the dynamical history of the Prometheus Pandora system, accounting for Pandora's migration due to tidal interactions with Saturn. This revealed several past cross-resonances with a low probability of capture, as well as a scenario in which the Prometheus-Pandora pair exhibited a co-orbital configuration.

astro-ph.EP↗

arXiv2025

Orbital Dynamics of Atlas (S XV): Its Current Orbit and the Recent Past

This study comprehensively analyzes Atlas's current orbit, focusing on the secular and resonant perturbations caused by Prometheus, Pandora, and Saturn's oblateness. We performed numerical integration of the exact equations of motion for a dense ensemble of Atlas clone satellites. Through spectral analysis and interpretation of these orbits on dynamical maps, we identified the domain of the 54:53 Prometheus-Atlas and 70:67 Pandora-Atlas mean-motion resonances, showing that Atlas lies on the boundary of the separatrices of each of these resonances. We also identified the domains for the multiplets $Ψ_{1}$, $Ψ_{2}$, $Ψ_{3}$ and $Ψ_{4}$ associated with 70:67 resonance. Additionally, we explored the variation in Prometheus's eccentricity, demonstrating that as eccentricity increases (or decreases) in the 54:53 resonance domain correspondingly decreases (or increases). This combined analysis, between the above mappings, revealed qualitatively the overlap between the 54:53 and 70:67 resonances, which are responsible for the chaotic behavior of Atlas's orbit. We quantified chaotic motion in frequency space and found that the vicinity of Atlas is characterized by weak to moderate chaos, rather than strong chaos. Finally, we investigated Atlas's recent past, considering Prometheus's migration under the influence of Saturn's tidal forces. This analysis reveals several resonances crossed in the past, particularly focusing on the Atlas-Prometheus pair, which exhibited a co-orbital configuration.

astro-ph.EP↗

arXiv2022

The current orbit of Methone (S/2004 S 1)

The Cassini spacecraft discovered many close-in small satellites in Saturnian system, and several of them exhibit exotic orbital states due to interactions with Mimas and the oblateness of the planet. This work is devoted to Methone, which is currently involved in a 15:14 Mean-Motion Resonance with Mimas. We give an in deep study the current orbit of Methone by analyzing and identifying the short, resonant and long-term gravitational perturbations on its orbit. In addition, we perform numerical integrations of full equations of motion of ensembles of close-in small bodies orbiting the non-central field of Saturn. Spectral analyses of the orbits and interpretation of them in dynamical maps allow us to describe the orbit and the dynamics of Methone in view of resonant and long-term dynamics. We show that the current geometric orbit of Methone is aligned with Mimas' due to a forced resonant component in eccentricity, leading to simultaneous oscillations of several critical angles of the expanded disturbing function. Thus, we explain the simultaneous oscillations of four critical arguments associated to the resonance. The mapping of the Mimas-Methone resonance shows that the domains of the 15:14 Mimas-Methone resonance are dominated by regular motions associated to the Corotation resonance located at eccentricities lower than $\sim 0.015$ and osculating semi-major axis in the interval 194,660-194,730 km. Methone is currently located deeply within this site.

astro-ph.EP↗