Misc,
How the presence of a gas giant affects the formation of mean-motion resonances between two low-mass planets in a locally isothermal gaseous disc
(2013)cite arxiv:1312.2147Comment: 10 pages, 11 figures, to be published in MNRAS.
Abstract
In this paper we investigate the possibility of a migration-induced resonance
locking in systems containing three planets, namely an Earth analog, a
super-Earth and a gas giant. The planets have been listed in order of
increasing orbital periods. All three bodies are embedded in a locally
isothermal gaseous disc and orbit around a solar mass star. We are interested
in answering the following question: Will the low-mass planets form the same
resonant structures with each other in the vicinity of the gas giant as in the
case when the gas giant is absent? When there is no gas giant in the system, it
has been already shown that if the two low-mass planets undergo a convergent
differential migration, they will capture each other in a mean-motion
resonance. For the choices of disc parameters and planet masses made in this
paper, the formation of the 5:4 resonance in the absence of the Jupiter has
been observed. In this work we add a gas giant on the most external orbit of
the system in such a way that its differential migration is convergent with the
low-mass planets. We show that the result of this set-up is the speeding up of
the migration of the super-Earth and, after that, all three planets become
locked in a triple mean-motion resonance. However, this resonance is not
maintained due to the low-mass planet eccentricity excitation, a fact that
leads to close encounters between planets and eventually to the ejection from
the internal orbits of one or both low-mass planets.