(ORDO NEWS) — Scientists have recreated conditions on the surface of Pluto’s moon Charon and designed the first model of its dynamic atmosphere.
Charon is one of the five moons of Pluto. It is so large that it makes sense to consider it part of the Pluto-Charon binary system.
With respect to the orbital plane, the system lies almost on its side, so when the seasons change, the poles are entirely under the sun’s rays.
Here are just a “year” there lasts 248 Earth years, so the “first spring days” in the hemispheres drag on for years. As a new study has shown, during the equinox twice a “year” under the influence of the sun’s rays on Charon, the strongest changes occur.
Charon’s surface is covered in layers of frozen methane, nitrogen, and possibly water ice. Under the heat of the sun, the frozen methane evaporates quickly, then to settle at the other pole. For this period – about four Earth years – the density of the atmosphere increases sharply by almost a thousand times.
It was believed that the red spot at the pole appears due to the interaction of solar ultraviolet radiation with “falling” methane. A new study has shown that the freezing process is too fast to form compounds that give a red color.
To understand what is happening, scientists reproduced the conditions of Charon’s surface at the new Center for Laboratory Experiments in Astrophysics and Space Sciences (CLASSE) at the Southwestern Research Institute (USA).
Experiments in an ultra-high vacuum chamber made it possible to determine the composition and color of hydrocarbons formed during freezing of methane under ultraviolet radiation.
To understand what is happening on the scale of the entire Charon, the team of researchers developed a new model of the thin atmosphere of the body. So it became known about the “explosive” pulsation of the atmosphere due to the change of seasons.
Combining the results of ultra-realistic experiments with the new model, the scientists found that at the poles of Charon, mainly ethane is formed – a colorless compound that cannot explain the red color. But the authors put forward a new hypothesis:
“We think that under the influence of ionizing radiation from the solar wind, frozen [under ultraviolet radiation] polar ice turns into more complex, red compounds that provide the mysterious satellite with a unique albedo,” explains Ujjwal Raut (Ujjwal Raut) , the main author of the article in Science Advances.
“Ethane is less volatile than methane and remains frozen after the equinox.” And over the next decades, under the influence of the solar wind, it is he who turns into reddish compounds. That is, this shade appears not in the process of freezing a new layer, but when the old one is exposed.
Earthlings saw the surface of Charon for the first and so far only time during the flyby of the interplanetary station “New Horizons” in 2015. Only then did scientists learn about the red spot at the pole.
Judging by the deep canyons that stretch along the equator, Charon had a turbulent geological past. Scientists are developing possible expeditions to Pluto and Charon, but none of them have yet been officially planned.
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