Saturn south pole features newly discovered decagon atmospheric structure

Astronomers have identified a new atmospheric phenomenon at Saturn’s south pole: a ten-sided jet stream known as a ‘decagon’. The discovery, published in Science Advances, was made possible through the Outer Planet Atmospheres Legacy (OPAL) program using observations from the Hubble Space Telescope.

Unlike the well-known, stable hexagon located at Saturn’s north pole, this decagon appears to be a recent and evolving formation. While the north pole's hexagon has remained stable for over 40 years, the southern decagon shows dynamic behavior and was not detected by the Cassini probe during its mission between 2004 and 2017. Researchers suggest the formation may have been triggered by seasonal changes on the planet.

The structure is an atmospheric wave produced by high-latitude winds that can exceed 400 km/h, though the decagonal pattern itself moves much slower, at approximately 9 km/h. The ten vertices exhibit a back-and-forth movement in a cycle of about 32 days. Scientists plan to continue monitoring the phenomenon using both the Hubble and James Webb telescopes to understand its evolution.