Floris, Manuel
(2022)

*A Comparative Analysis of Dynamical Models for Tidal Dissipation in Natural Satellite Ephemerides.*
[Laurea magistrale], Università di Bologna, Corso di Studio in

Aerospace engineering [LM-DM270] - Forli', Documento full-text non disponibile

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## Abstract

The study of the tides of a celestial bodies can unveil important information about their interior as well as their orbital evolution.
The most important tidal parameter is the Love number, which defines the deformation of the gravity field due to an external perturbing body. Tidal dissipation is very important because it drives the secular orbital evolution of the natural satellites, which is even more important in the case of the the Jupiter system, where three of the Galilean moons, Io, Europa and Ganymede, are locked in an orbital resonance where the ratio of their mean motions is 4:2:1. This is called Laplace resonance. Tidal dissipation is described by the dissipation ratio k2/Q, where Q is the quality factor and it describes the dampening of a system.
The goal of this thesis is to analyze and compare the two main tidal dynamical models, Mignard's model and gravity field variation model, to understand the differences between each model with a main focus on the single-moon case with Io, which can help also understanding better the differences between the two models without over complicating the dynamical model.
In this work we have verified and validated both models, we have compared them and pinpointed the main differences and features that characterize each model. Mignard's model treats the tides directly as a force, while the gravity field variation model describes the tides with a change of the spherical harmonic coefficients.
Finally, we have also briefly analyzed the difference between the single-moon case and the two-moon case, and we have confirmed that the governing equations that describe the change of semi-major axis and eccentricity are not good anymore when more moons are present.

Abstract

The study of the tides of a celestial bodies can unveil important information about their interior as well as their orbital evolution.
The most important tidal parameter is the Love number, which defines the deformation of the gravity field due to an external perturbing body. Tidal dissipation is very important because it drives the secular orbital evolution of the natural satellites, which is even more important in the case of the the Jupiter system, where three of the Galilean moons, Io, Europa and Ganymede, are locked in an orbital resonance where the ratio of their mean motions is 4:2:1. This is called Laplace resonance. Tidal dissipation is described by the dissipation ratio k2/Q, where Q is the quality factor and it describes the dampening of a system.
The goal of this thesis is to analyze and compare the two main tidal dynamical models, Mignard's model and gravity field variation model, to understand the differences between each model with a main focus on the single-moon case with Io, which can help also understanding better the differences between the two models without over complicating the dynamical model.
In this work we have verified and validated both models, we have compared them and pinpointed the main differences and features that characterize each model. Mignard's model treats the tides directly as a force, while the gravity field variation model describes the tides with a change of the spherical harmonic coefficients.
Finally, we have also briefly analyzed the difference between the single-moon case and the two-moon case, and we have confirmed that the governing equations that describe the change of semi-major axis and eccentricity are not good anymore when more moons are present.

Tipologia del documento

Tesi di laurea
(Laurea magistrale)

Autore della tesi

Floris, Manuel

Relatore della tesi

Correlatore della tesi

Scuola

Corso di studio

Indirizzo

CURRICULUM SPACE

Ordinamento Cds

DM270

Parole chiave

Tidal dissipation, orbital dynamics, Ephemerides

Data di discussione della Tesi

13 Ottobre 2022

URI

## Altri metadati

Tipologia del documento

Tesi di laurea
(NON SPECIFICATO)

Autore della tesi

Floris, Manuel

Relatore della tesi

Correlatore della tesi

Scuola

Corso di studio

Indirizzo

CURRICULUM SPACE

Ordinamento Cds

DM270

Parole chiave

Tidal dissipation, orbital dynamics, Ephemerides

Data di discussione della Tesi

13 Ottobre 2022

URI

Gestione del documento: