Hundreds of tons of atmospheric nitrogen is escaping from Pluto every hour, but no matter how much leaks into space, the dwarf planet appears to have an endless supply of the gas, causing a team of researchers to figure out exactly where all of this nitrogen is coming from.
In a new study published this month in The Astrophysical Journal Letters, Kelsi Singer and Alan Stern of the Southwest Research Institute (SwRI) investigated several different, potential sources that could be replenishing the nitrogen, including whether comets could be delivering enough gas to make up for what is lost, or if impactors were excavating subsurface nitrogen.
“More 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 as the result of heating by ultraviolet light from the sun,” Singer, a postdoctoral researcher at SwRI, said in a statement.
“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,” she added. “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.”
Recent geologic activity may be linked to nitrogen replenishment
According to Space.com, Pluto’s atmosphere has 10,000 times less surface pressure than Earth, and as a result, hundreds of tons of nitrogen are escaping the dwarf planet’s atmosphere per hour. Nonetheless, the atmosphere remains 98 percent nitrogen, meaning replacement gas had to come from somewhere. The new study suggests that it is coming from within.
Data obtained by the New Horizons spacecraft included new images of Pluto’s land forms suggesting that heat is rising beneath the surface, with dark matter troughs accumulating or bubbling up between flat segments of crust. According to the study authors, this phenomenon could be related to the nitrogen issue.
“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, principal investigator of New Horizons. “As data from New Horizons comes in, we will be very interested to see if this proves true.”
“We currently have only a tiny fraction of the data back from the New Horizons flyby, but the fact that there are young-looking areas on Pluto hints at relatively recent geologic activity,” Singer added in a NASA blog post. “Stay tuned as we get more data back… over the coming months, which will refine our estimates of Pluto’s atmospheric escape and provide more images of Pluto’s surface to assess the types and timing of geologic activity.”
(Image credit: NASA/JHUAPL/SwRI)
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