A recent study shows that Pluto's dune systems contain wind-driven frozen methane grains with possible remnants of nitrogen ice.
NASA's New Horizons mission, launched on the dwarf planet in July 2015, found that Pluto has towering mountains, but rather of water ice than rock; wide levels of frozen nitrogen and other exotic materials; and blue sky through a wispy atmosphere that contains no significant oxygen.
Recent studies show another foreign parallel in which Pluto has a vast dune system. The grains that make up the windswept hills are certainly not sand.
The new discovery "shows us that Pluto's atmosphere and surface interact in a way that geologically / geomorphologically changes the surface," said study leader Matt Telfer, a lecturer in physical geography at the University of Plymouth in England
"The is exciting, not only because it shows the dynamics of these small, cold, dark, distant worlds, but also for their conclusions for very early solar radiation system bodies, "Telfer says in a Space.com report.
Telfer and his colleagues analyzed the footage that New Horizons captured during his epic flyby. They noticed within Sputnik Planitia a complex of ridges, a 620-mile-wide (1
The ridges curl in a 47-mile-wide (75 km) splinter on the western edge of Sputnik Planitia, where the plain joins the 5 km Al-Idrisi Montes Mountains. The newly identified features are very similar to the wind-sculpted dunes, and that's exactly what they are, according to the study team.
"Sublimation pits" are sites where sunlight has relatively large amounts of icy material for sublimation or transition directly from the solid phase to gas. The images of New Horizons have uncovered thousands of such depressions through Sputnik Planitia, and a series of aligned pits was the most viable alternative explanation for the dune features, as Telfer and his colleagues wrote in the new study.
Sublimation is an important part of the history of the dunes, the researchers found. They performed modeling that suggested that Pluto's winds were strong enough to produce the Sputnik-Planitia dune system as long as the blown grains were already in the air.
"What makes this discovery surprising is that the sediment can be mobilized despite Pluto's weak atmosphere, with a surface pressure (1 Pa) that is 100,000 times lower than that on Earth," wrote Alexander Hayes, an assistant professor of Astronomy at Cornell University, which was not involved in the new study, in an accompanying "Perspectives"
Telfer expressed similar feelings: "It was hard to see how the wind can affect everything until you do the math."
"The new study is far from the last word on Pluto's dunes," said Hayes, who also directs Cornell's Spacecraft Planetary Imaging Facility.