Possible Obliquity variations of the planets during planetary migration

• Grant number: 16/07046-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: July 01, 2016
• End date: March 31, 2018
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Positional Astronomy and Celestial Mechanics
• Principal Investigator: Tadashi Yokoyama
• Grantee: Marina Gonzaga de Oliveira
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

It is almost a consensus that the giant planets were formed with almost zero obliquity. However except Jupiter, the present obliquity of Saturn, Uranus and Neptune, are far from zero. They are : 25.6 ,97.8, 28.3, respectively. Usually, the reason of these high values are linked to gravitational effects like collisions or capture into resonances. In this work we intend to build an averaged model that governs the long term dynamics of the obliquity of a planet under the influence of the Sun and a satellite X placed at different orbits and with different masses. We adopt Andoyer variables, so as they are canonical, the averaging can be done rigorously provided that they are also action-angle variables. This averaged model is well suited to investigate the present obliquity of Neptune in the context of the planetary migration and also in the case of some exoplanets (Armstrong et al 2013). Apparently Neptune is the only planet that does not have any primordial regular satellite. Therefore contrary to Uranus' case, there is no risk in destabilizing eventual regular Neptune's satellites, an issue faced by Boué -Laskar in the Uranus problem. On the other hand, for Neptune, it seems that satellite X does not need to be so massive as in the case of Uranus.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

OLIVEIRA, Marina Gonzaga de. Possible variations of the obliquities of the planets. 2018. Master's Dissertation - Universidade Estadual Paulista (Unesp). Instituto de Geociências e Ciências Exatas. Rio Claro Rio Claro.