Titan observed naked in solar wind for first time

Monday, February 02, 2015

Researchers studying data from NASA's Cassini mission have observed that Saturn's largest moon, Titan,
behaves much like Venus, Mars or a comet
[PHOTO: NASA/JPL-Caltech] 
Washington: Saturn’s largest moon, Titan, looks more like Mars or Venus than astronomers ever suspected—at least when it comes to suffering a severe strike from the solar wind.

This diagram depicts conditions observed by NASA's Cassini spacecraft during a flyby in Dec. 2013, when Saturn's magnetosphere was highly compressed, exposing Titan to the full force of the solar wind. 
Conditions observed by NASA’s Cassini spacecraft during a flyby in December 2013
In analyzing data from the encounter, scientists with Cassini's magnetometer team observed that the giant moon interacted with the solar wind much like the planets Mars and Venus, or a comet -- none of which possess their own internal magnetic field. Specifically, they saw that the solar wind draped itself around Titan, creating a shockwave that formed around Titan where the full-force solar wind rammed into the moon's atmosphere.

Previously, researchers had thought Titan would have a different sort of interaction with the solar wind because of the moon's complex atmospheric chemistry.

Titan spends about 95 percent of its time around Saturn, within the planet’s strong, protective magnetosphere. So Cassini mission planners were excited to observe the moon exposed and naked in the solar wind during the 2013 flyby. 

The visit allowed them to see the shock wave produced around Titan as the fast-flowing solar particles slammed directly into the moon’s unprotected atmosphere.

“We observed that Titan interacts with the solar wind very much like Mars, if you moved it to the distance of Saturn,” said Cesar Bertucci of the Institute of Astronomy and Space Physics in Buenos Aires, who led the research with colleagues from the Cassini mission.

Despite the complicated chemistry of thick methane-rich skies, Titan’s atmosphere seems to have responded to the solar wind in essentially the same way as the red planet, which has a much thinner atmosphere than Earth or Saturn's big moon.

“We thought Titan in this state would look different,” Bertucci said. “We certainly were surprised.”

Now researchers believe these new findings suggest that regardless of where unmagnetized planets lie in the solar system, they all interact with the solar wind in the same way.

Titan is the second largest moon in the entire solar system and the only one to possess a thick atmosphere. Not surprisingly, it is the brightest and easiest of the 62 moons, and counting, of Saturn to spot.
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