Astronomers Observe Relative Hot Spot on Saturn Polar Cap

Astronomers using the giant Keck I telescope atop Mauna Kea have discovered a hot spot at the tip of Saturn’s south pole.

The infrared images suggest a warm polar vortex -- a large-scale weather pattern likened to a jet stream on Earth that occurs in the upper atmosphere. It’s the first such hot vortex discovered in the solar system.

The team of scientists says the images are the sharpest thermal views of Saturn ever taken from the ground. The team’s work was published in Friday’s edition of the journal Science.

This warm polar cap is believed to contain the highest temperatures on Saturn, about minus 188 degrees Fahrenheit. While still very cold, that is about 20 degrees warmer than other spots on the planet.

Earth’s Arctic Polar Vortex is typically located over eastern North America in Canada, and plunges cold arctic air to the northern Plains in the United States.

Polar vortices are found on Earth, Jupiter, Mars and Venus, and are colder than their surroundings. The new images from the Keck Observatory show the first evidence of a polar vortex at much warmer temperatures.

“Saturn’s is the first hot polar vortex that we’ve seen because it’s been sitting in the sunlight for about 18 years,” said the report’s lead author, Glenn S. Orton, a scientist at NASA’s Jet Propulsion Laboratory in La Canada Flintridge.

Saturn, which takes many Earth years to orbit the sun, just had its summer solstice in 2002.

“If the increased southern temperatures are solely the result of seasonality, then the temperature should increase gradually with increasing latitude, but it doesn’t,” Orton said. “We see that the temperature increases abruptly by several degrees near 70 degrees south and again at 87 degrees south.

“A really hot thing within a couple degrees of the pole is something I don’t understand at all,” Orton said.