Titan Seasons Documented
September 28, 2012

After 30 Years, Titan’s Seasons Are Now Documented

Lee Rannals for redOrbit.com — Your Universe Online

As the fall season starts to ramp up here in the U.S., observations show Saturn's moon Titan has its own drastic seasonal changes.

Astronomers presented findings at the European Planetary Science Congress on Friday about Titan's seasonal changes for the past 30 years.

“As with Earth, conditions on Titan change with its seasons," Dr. Athena Coustenis from the Paris-Meudon Observatory in France, who analyzed the data, said in a statement. "We can see differences in atmospheric temperatures, chemical composition and circulation patterns, especially at the poles."

She said hydrocarbon lakes form around the north polar region during winter due to colder temperatures and condensation, while a haze layer surrounding Titan at the northern pole is significantly reduced during the equinox due to the atmospheric circulation patterns.

"This is all very surprising because we didn´t expect to find any such rapid changes, especially in the deeper layers of the atmosphere," Coustenis said in the statement.

Solar radiation is the main cause for these cycles because it is the dominant energy source for Titan's atmosphere.

Solar radiation helps to break up the nitrogen and methane present, creating more complex molecules like ethane, and acting as the driving force for chemical changes.

Titan is included at about 27 degrees, which is similar to Earth, so the cause of the moon's seasons is the same as ours. This cause is due to sunlight reaching different areas with varying intensity due to the tilt.

“It´s amazing to think that the Sun still dominates over other energy sources even as far out as Titan, over 1.5 billion kilometers (930 million miles) from us," Coustenis said in the statement.

The astronomers used data from the Voyager 1 spacecraft, the Infrared Space Observatory and Cassini.

Each season on Titan lasts for around 7.5 years, while the moon's host planet, Saturn, takes 29.5 years for it to orbit around the Sun. Having 30 years of data enabled the astronomers to have a complete record of Titan's seasons.

“Titan is the best opportunity we have to study conditions very similar to our own planet in terms of climate, meteorology and astrobiology and at the same time a unique world on its own, a paradise for exploring new geological, atmospheric and internal processes," Coustenis said.