University of Arizona | 2019 Apr 29
While searching for the origins of Titan’s methane and the organics that coat its surface, UA researchers made the unexpected discovery of a large ice feature on Saturn's largest moon.
Rain, seas and a surface of eroding organic material can be found both on Earth and on Saturn’s largest moon, Titan. However, on Titan it is methane, not water, that fills the lakes with slushy raindrops.
While trying to find the source of Titan's methane, University of Arizona researcher Caitlin Griffith and her team discovered something unexpected – a long ice feature that wraps nearly half way around Titan. ...
On Titan, atmospheric methane molecules are continuously broken apart by sunlight. The resulting atmospheric haze settles to the surface and accumulates as organic sediments, rapidly depleting the atmospheric methane.
This organic veneer is made up of the material of past atmospheres.
There is no obvious source of methane, except from the evaporation of methane from the polar lakes. But Titan’s lakes contain only one-third of the methane in Titan’s atmosphere and will be exhausted soon by geological time scales.
One theory is that the methane could be supplied by subsurface reservoirs that vent methane into the atmosphere. Prior studies of Titan indicate the presence of a singular region called Sotra, which looks like cryo-volcano, with icy flow features.
Griffith’s team set out to study the composition of Titan’s surface, partly hoping to find subtle small cryo-volcanos candidates. They analyzed half of Titan’s surface and none were detected, but Sotra was found to be exceptional in that it exhibits the strongest ice features.
Yet the major ice feature the researchers found was completely unexpected. It consists of a linear ice corridor that wraps around 40 percent of Titan's circumference. ...
A corridor of exposed ice-rich bedrock across Titan’s tropical region ~ Caitlin A. Griffith et al
- Nature Astronomy (online 29 Apr 2019) DOI: 10.1038/s41550-019-0756-5