Even though it’s been sixteen years already since Pluto is no longer considered a planet, it still represents a good study material for astronomers. However, they’re now shifting their focus on Charon, which is the largest of the five moons of the dwarf planet from the edge of our Solar System.
Scientists had been wondering why the red cap exists on Charon, and it’s now, thanks to researchers from the Southwest Research Institute (SwRI), that an answer might finally exist. SciTechDaily reveals their new study based on data from the New Horizons mission of NASA, as well as on exospheric modeling and lab experiments.
Dr. Ujjwal Raut from SwRI, who’s also the lead author of the new study, explained as SciTechDaily quotes:
Our findings indicate that drastic seasonal surges in Charon’s thin atmosphere, as well as light breaking down the condensing methane frost, are key to understanding the origins of Charon’s red polar zone,
This is one of the most illustrative and stark examples of surface-atmospheric interactions so far observed at a planetary body.
Raut also explained, as the same source quotes:
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.
Besides Charon, the other four moons of Pluto are Kerberos, Nix, Hydra, and Styx. Charon is easily the largest of them all, as it measures a diameter of 1,212 kilometers. The other natural satellites of Pluto don’t even have spherical shapes.
It seems incredible that Pluto has five moons while Earth has only one. Pluto is a lot smaller than our planet – having a radius of 1,151 kilometers, Pluto has a width that’s about six times smaller than that of our planet.
You can see the new study on Charon as it was published here.