How Mimas rocks Anthe

The 10:11 resonance explained.

Published 2026-10-23

Anthe is visibly affected by a perturbing 10:11 mean-longitude resonance with much larger Mimas.^[1]

What it means

The two moons’ orbital periods are close to a ratio of whole numbers, so Mimas tugs Anthe in the same way again and again.

The effect

Anthe’s semi-major axis varies by about 20 km over about two Earth years.^[1]

Mimas

Mimas is about 396 km across — the smallest known body that is roughly round due to its own gravity.^[5]

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