Deep rotating convection generates the polar hexagon on Saturn

Abstract

Numerous land and space-based observations have established that Saturn has a persistent hexagonal flow pattern near its north pole. While observations abound, the physics behind its formation is still uncertain. Although several phenomenological models have been able to reproduce this feature, a self-consistent model for how such a large-scale polygonal jet forms in the highly turbulent atmosphere of Saturn is lacking. Here we present a 3D fully-nonlinear anelastic simulation of deep thermal convection in the outer layers of gas giant planets which spontaneously generates giant polar cyclones, fierce alternating zonal flows, and a high latitude eastward jet with a polygonal pattern. The analysis of the simulation suggests that self-organized turbulence in the form of giant vortices pinches the eastward jet, forming polygonal shapes. We argue that a similar mechanism is responsible for exciting Saturn's hexagonal flow pattern.

11 pages, 4 main and 5 supplementary figures, 1 animation, 42 references

References in corpus (5)

• Large-scale vortices in rapidly rotating Rayleigh-Bénard convection
• High-resolution calculation of the solar global convection with the reduced speed of sound technique: II. Near surface shear layer with the rotation
• Saturn's deep atmospheric flows revealed by the Cassini Grand Finale gravity measurements
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Cited by in corpus (3)

• Deep convection-driven vortex formation on Jupiter and Saturn
• The number and location of Jupiter's circumpolar cyclones explained by vorticity dynamics
• Investigating Barotropic Zonal Flow in Jupiter's Deep Atmosphere using Juno Gravitational Data