Scientists Explain Pluto’s Moon Charon’s Red Spot

a possible Charon explanation for mysterious red hat at the moon’s north poleIt may have been discovered from the planet Pluto by researchers at the Southwest Research Institute in San Antonio, United States. The red dot, once seen as a diffuse blob of light, became the subject of controversy in scientific circles after the pioneering flyby of NASA’s New Horizons space probe in July 2015.

Shortly after the land probe encountered the dwarf planet, New Horizons scientists said the rust-colored speck (called the Mordor Macula) was methane captured directly from Pluto’s surface and was slowly “cooked” by the Sun’s ultraviolet light. But the hypothesis had to be tested.

Modeling Charon

To determine what really happened to Pluto’s moon, the researchers used exoplanet modeling to simulate the tilting and tilting motion of the planetary system. The result was that the stain could have been a result of the spring sun. Thus, a thin layer of methane ice several microns thick will evaporate from one pole to the other.

However, modeling rejected the model because these movements were too fast. – Just a few years from the orbital period of 248 Earth years – for the frozen methane to absorb enough Lyman-alpha radiation to decompose into tholins, sticky organic residues formed by chemical reactions fueled by the ultraviolet glow of sunlight.

Answer: ethane

However, ethane, another hydrocarbon “prime” of methane, reacts differently. According to planetary scientist Ujjwal Raut, lead author of the study, “ethane is less volatile than methane and it remains frozen on the surface of Charon long after spring has risen.”

“Exposure to the solar wind can transform ethane into persistent reddish surface deposits and contribute to Charon’s red cap,” the author concludes.

ARTICLE ScienceAdvances – DOI: 10.1126/sciadv.abq5701.