Geological activity on Pluto possibly aiding Nitrogen resupply: Study

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Geological activity on Pluto aiding Nitrogen resupply: Study
In the northern region of Pluto’s Sputnik Planum, swirl-shaped patterns of light and dark suggest that a surface layer of exotic ices has flowed around obstacles and into depressions, much like glaciers on Earth. Credits: NASA/JHUAPL/SwRI

New Horizons Pluto flyby has revealed a lot about the dwarf planet in great detail and as NASA scientists continue to receive more and more data that was captured during the closest encounter, researchers have tried to look for a possible explanation about what could be aiding Nitrogen resupply on Pluto.

Latest images from New Horizons spacecraft have revealed a diverse surface on the dwarf planet and while the spacecraft was flying away from Pluto, it managed to capture an image that indicated abundance of Nitrogen in Pluto’s atmosphere. Further analysis revealed that because of Pluto’s small mass, hundreds of tons of atmospheric nitrogen is escaping into space each hour.

With such large quantities of nitrogen escaping, one logical question would be where is all the nitrogen coming from? Dr. Kelsi Singer, a postdoctoral researcher at Southwest Research Institute, and her mentor Dr. Alan Stern, SwRI associate vice president and the science lead for the New Horizons mission, outlined some of the likely sources in a paper titled, “On the Provenance of Pluto’s Nitrogen”. The paper was published in The Astrophysical Journal Letters- just a day after the spacecraft’s closest encounter with the icy dwarf planet.

The paper was published before New Horizons sent images of the flyby that revealed nitrogen ice flows as well as nitrogen escaping the atmosphere. Researchers have contemplated that more amounts of nitrogen has to come from somewhere to resupply both the nitrogen ice that is moving around Pluto’s surface in seasonal cycles, and the nitrogen that is escaping off the top of the atmosphere. They looked at a number of different ways that nitrogen might be resupplied.

One of the possible cause could be comets that might be bringing enough nitrogen to Pluto’s surface to resupply what is escaping its atmosphere. They also looked at whether craters made by the comets hitting the surface could excavate enough nitrogen – but that would require a very deep layer of nitrogen ice at the surface, which is not proven. The team also studied whether craters could expose more surface area, by punching through surface deposits that would likely be built up over time.

“We found that all of these effects, which are the major ones from cratering, do not seem to supply enough nitrogen to supply the escaping atmosphere over time,” continued Singer. “While it’s possible that the escape rate was not as high in the past as it is now, we think geologic activity is helping out by bringing nitrogen up from Pluto’s interior.”

And while the data weren’t in before this paper was written, the newest images of Pluto show land forms that suggest heat is rising beneath the surface, with troughs of dark matter either collecting, or bubbling up, between flat segments of crust, which could be related.

“Our pre-flyby prediction, made when we submitted the paper, is that it’s most likely that Pluto is actively resupplying nitrogen from its interior to its surface, possibly meaning the presence of ongoing geysers or cryovolcanism,” said Stern. “As data from New Horizons comes in, we will be very interested to see if this proves true.”