Scientists identify a possible source of Charon’s red mantle

Southwest Research Institute scientists have combined data from NASA’s New Horizons mission with new lab experiments and extra-atmospheric modeling to reveal the possible makeup of the red mantle on Pluto’s moon Charon and how it formed. The new findings suggest that intense seasonal elevations in Charon’s thin atmosphere combined with light that refracts the condensing methane frost may be key to understanding the origins of Charon’s red polar regions. Credit: NASA/Johns Hopkins APL/SwRI

Southwest Research Institute scientists have combined data from NASA’s New Horizons mission with new lab experiments and extra-atmospheric modeling to reveal the possible makeup of the red mantle on Pluto’s moon Charon and how it formed. This first-ever description of Charon’s dynamic methane atmosphere using new experimental data provides a fascinating glimpse into the origins of this moon’s red spot as described in two recent papers.

“Before New Horizons, the best Hubble images of Pluto revealed a hazy mass of reflected light,” said Randy Gladstone of SwRI, a member of the New Horizons science team. “In addition to all the remarkable features detected on Pluto’s surface, a flyby of Pluto’s surface revealed an unusual feature of Charon, a sudden red mantle centered at its north pole.”

Shortly after the 2015 encounter, New Horizons scientists suggested that a reddish “tholin-like” substance at Charon’s pole could be synthesized by ultraviolet radiation that breaks down methane molecules. It is captured after escaping from Pluto and then frozen in the polar regions of the Moon during the long winter nights. Tholene is a sticky organic residue formed by chemical reactions powered by light, in this case Lyman-alpha’s ultraviolet glow scattered by interplanetary hydrogen molecules.

Dr. said. Ujwal Raut, lead author of a research paper titled “Sharon Refractories Factory” in the journal science progress. “This is one of the most illustrative and clear examples of surface-atmospheric interactions so far observed in a planetary body.”

The team realistically replicated Charon’s surface conditions at SwRI’s new Center for Laboratory Astrophysics and Space Science Experiments (CLASSE) to measure the composition and color of hydrocarbons produced in Charon’s winter hemisphere while methane freezes under the Lyman-alpha glow. The team inserted measurements into a new atmospheric model of Charon to show methane decaying into residue in the Arctic Charon Spot.

“Our team’s new ‘photodynamic decomposition’ experiments provided new frontiers for the contribution of interplanetary Lyman-alpha to the synthesis of red Charon material,” said Raut. .”

SwRI scientists have also developed new computer simulations to model Charon’s thin methane atmosphere.

Dr. said. Ben Thewlis, lead author of a related paper titled “Extreme exosphere dynamics in Charon: Implications for the red spot” in Geophysical Research Letters.

The team inserted results from ultra-realistic SwRI experiments into an atmospheric model to estimate the distribution of complex hydrocarbons arising from methane decomposition under the influence of ultraviolet light. The pattern contains polar regions that generate mainly ethane, a colorless substance that does not contribute to the formation of a reddish tint.

“We believe that ionizing radiation from the solar wind decomposes the polar frost cooked with Alpha Lymans to form more complex, redder materials responsible for the unique whiteness on this mysterious moon,” said Raut. “Ethane is less volatile than methane and remains frozen on Charon’s surface long after spring sunrise. Exposure to solar winds may convert ethane into permanent reddish surface deposits that contribute to Charon’s red mantle.”

Dr. said. Josh Kamer, who has the ongoing support of NASA’s new Frontier Data Analysis Program.


Pluto paints its largest moon, Charon, red


more information:
Ben Teolis et al, Charon’s extreme exosphere dynamics: implications for the red spot, Geophysical Research Letters (2022). doi: 10.1029/2021GL097580

Ujwal Raut et al., Sharon Refractories Factory, science progress (2022). DOI: 10.1126 / sciadv.abq5701

Presented by the Southwest Research Institute

the quote: Scientists Identify Possible Source of Charon’s Red Cap (2022, June 21) Retrieved June 22, 2022 from https://phys.org/news/2022-06-scientists-source-charon-red-cap.html

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