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| Author(s): |
Gustavo Oliveira Madeira
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Guaratinguetá. 2019-03-08. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Guaratinguetá |
| Defense date: | 2019-02-20 |
| Advisor: | Silvia Maria Giuliatti Winter |
| Abstract | |
Anthe, Methone and Aegaeon are three tiny saturnian moons. They are coorbital to planetary arcs and are trapped in corotation eccentric resonances with Mimas: 10:11 Anthe’s arc, 14:15 Methone’s arc and 7:6 G ring arc (Aegaeon’s arc). In this work we studied the dynamics of the particles trapped in the corotation eccentric resonances under the effects of dissipative forces (solar radiation force and plasma drag) and coorbitals moonlets. The m + 1:m corotation eccentric resonance creates m sites where the particles will be azimuthally confined for more than 100 thousand years. When satellites are located in the sites, the particles quickly collide with them and these sites are cleaned in a few hundred years. We verified an increase in the lifetime of the sites with the satellites’ radii, for moons with radius of the order of meters, and a decrease in the lifetime with an increase of the satellites’ radii, for kilometer-sized satellites. Satellites with radii of the order of meters only disturb the particles’ orbits, so the particles perform large excursions in relation to the site’s center. Satellites with kilometric radii azimuthally confine the particles, wich remain in resonance with Mimas and with the coorbital satellite. The solar radiation force and plasma drag effects on the semimajor axis remove particles from the azimuthal confinement and the effects on the eccentricity favor collisions with the satellites. The sites of the 7:6, 14:15 and 10:11 corotation resonance, if composed by particles smaller than 10 μm, have lifetimes of less than 140, 25 and 15 years, respectively. The time to the satellites replenish the site due the interplanetary projectiles collisions process are, at least, an order of magnitude greater than the sites’ lifetimes. Thus, the arc are transient structures. For the G ring arc, we obtain that particles smaller than 10 μm leave the arc or collide in less than 30 years and those ejected by Aegaeon collide in less than 300 years. So, Aegaeon is not the arc and ring source. We also analyzed the Neptune’s ring arcs, assuming that they are azimuthally confined by coorbital moons. We verified that the Fraternité and Egalité arcs are in 42:43 Lindblad eccentric resonance with Galatea and the Liberté and Courage arcs do not. Due to this, the particles of the both last ones pass through close encounters with the satellites and leave the arcs. If we include the solar radiation force, all the particles leave the arcs, however the particles initially at Fraternité and Egalité remain in the close region. So we explain the dispersion of the arcs of Neptune (AU) | |
| FAPESP's process: | 16/24488-0 - Orbital evolution study of particles in Lindblad and corotation resonances and under influence of coorbitals satellites: planetary arcs application |
| Grantee: | Gustavo Oliveira Madeira |
| Support Opportunities: | Scholarships in Brazil - Master |