Saturn's Rings Produce 'Rain' That Affects The Planet's Temperature
Saturn is the first planet known to show significant interaction between its atmosphere and ring system, according to NASA-funded researchers at the University of Leicester.
Using the W.M. Keck Observatory on Mauna Kea in Hawaii, astronomers witnessed the gas giant's rings "rain" charged water particles down onto Saturn's ionosphere in much larger volumes and across more area that ever seen before, revealing the rain influences the temperature structure of parts of Saturn's upper atmosphere.
"The main effect of ring rain is that it acts to 'quench' the ionosphere of Saturn, severely reducing the electron densities in regions in which it falls," said James O'Donoghue, lead author of the paper that appeared in the journal Nature this week.
The study will help scientists better understand the Saturn's atmosphere and how the planet's ring system has evolved over time.
According to Discovery News, highly charged ice particles have been known to be transported from Saturn's rings to the planet via its powerful magnetosphere, but this is the first time global changes to the temperature and composition of Saturn's ionosphere have been confirmed.
Dark bands probably signifying rain in Saturn's upper atmosphere were witnessed in the 1980s, but those bands were not seen again until the new study.
The findings set Saturn apart from its cosmic neighbor Jupiter, another gas giant. Astronomers expected Saturn to have an equatorial region that grows uniformly, like Jupiter's and Earth's.
"Where Jupiter is glowing evenly across its equatorial regions, Saturn has dark bands where the water is falling in, darkening the ionosphere," said Tom Stallard, a paper co-author at Leicester, according to a NASA statement. "We're now also trying to investigate these features with an instrument on NASA's Cassini spacecraft. If we're successful, Cassini may allow us to view in more detail the way that water is removing ionized particles, such as any changes in the altitude or effects that come with the time of day."