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Orbital evolution of Saturn's satellites due to the interaction between the moons and massive Saturn's rings

Status Report From: arXiv.org e-Print archive
Posted: Wednesday, July 22, 2020

Ayano Nakajima, Shigeru Ida, Yota Ishigaki

Saturn's mid-sized moons (satellites) have a puzzling orbital configuration with trapping in mean-motion resonances with every other pairs (Mimas-Tethys 4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration on the basis of Crida & Charnoz's model of satellite formation from a hypothetical ancient massive rings, adjacent pairs must pass 1st-order mean-motion resonances without being trapped. The trapping could be avoided by fast orbital migration and/or excitation of the satellite's eccentricity caused by gravitational interactions between the satellites and the rings (the disk), which are still unknown. In our research, we investigate the satellite orbital evolution due to interactions with the disk through full N-body simulations. We performed global high-resolution N-body simulations of a self-gravitating particle disk interacting with a single satellite. We used N∼105 particles for the disk. Gravitational forces of all the particles and their inelastic collisions are taken into account. As a result, dense short-wavelength wake structure is created by the disk self-gravity and global spiral arms with m∼ a few is induced by the satellite. The self-gravity wakes regulate the orbital evolution of the satellite, which has been considered as a disk spreading mechanism but not as a driver for the orbital evolution. The self-gravity wake torque to the satellite is so effective that the satellite migration is much faster than that was predicted with the spiral arms torque. It provides a possible model to avoid the resonance capture of adjacent satellite pairs and establish the current orbital configuration of Saturn's mid-sized satellites.

Comments: (6 pages, 4 figures, Accepted in A&A)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:2007.10745 [astro-ph.EP] (or arXiv:2007.10745v1 [astro-ph.EP] for this version)

Submission history

From: Ayano Nakajima 

[v1] Tue, 21 Jul 2020 12:17:13 UTC (1,878 KB)

https://arxiv.org/abs/2007.10745

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