Root NationNewsScientists have identified a possible source of Pluto's moon red cap

Scientists have identified a possible source of Pluto’s moon red cap


Scientists at the Southwestern Research Institute have combined NASA’s New Horizons mission data with new lab experiments and exosphere modeling to determine the likely composition of the red cap on Pluto’s moon Charon, and the ways of its formation.

Scientists have previously suggested that red tolin-like material enveloping Charon’s pole could be synthesized by breaking down methane molecules in ultraviolet light. They fall on Charon from Pluto and then freeze in the polar regions of the moon during long winter nights. Tolins are sticky organic residues formed as a result of chemical reactions under the influence of light, in this case the ultraviolet glow of Lyman-alpha, scattered by interplanetary hydrogen molecules.


The team realistically reproduced the conditions on the Charon surface to measure the composition and color of hydrocarbons. Scientists have introduced the results of measurements into a new atmospheric model to show how methane decomposes into residues in the northern polar spot of Charon. They also developed a new computer simulation of Charon’s thin methane atmosphere. The model indicates “explosive” seasonal ripples in Charon’s atmosphere caused by extreme changes in conditions during Pluto’s long journey around the Sun.


The team incorporated the results of ultra-realistic experiments into the atmospheric model to estimate the distribution of complex hydrocarbons formed during the decomposition of methane under the influence of ultraviolet light. In the model, the polar zones mainly generate ethane, a colorless substance that could not color the Charon’s north pole red.

Pluto & Charon

“We think ionizing radiation from the solar wind decomposes the Lyman-alpha-cooked polar frost to synthesize increasingly complex, redder materials responsible for the unique albedo on this enigmatic moon. Ethane is less volatile than methane and stays frozen to Charon’s surface long after spring sunrise. Exposure to the solar wind may convert ethane into persistent reddish surface deposits contributing to Charon’s red cap,” – scientists concluded.

You can also help Ukraine fight with Russian occupants via Savelife or via an official page of the National Bank of Ukraine.

Read also:

Donate us

Similar articles

Notify of
Inline Feedbacks
View all comments