NEWS FROM CHARON
Fantasy features
Various features on the surface of Charon have been given official names by the International Astronomical Union Working Group for Planetary System Nomenclature. The names reflect travellers and explorers, especially those with mysterious destinations. Dorothy crater, for example, is named after the protagonist from The Wizard of Oz, while Caleuche Chasma is named for the mythological ghost ship that travels the seas around the small island of Chiloé off the coast of Chile. Mandjet Chasma is named for one of the boats in Egyptian mythology that carried the Sun god Ra across the sky each day, and Nemo crater honours the captain of the Nautilus, the submarine in Jules Verne’s novels.
What’s in the cap?
Charon’s north polar cap is different to the rest of its surface, and Pluto may be sharing its atmosphere with its largest moon. A study from Lowell Observatory in Arizona modelled conditions on Charon over the past few billion years and discovered that radiation had been stripping the hydrogen from frozen methane on the dwarf planet’s surface.
This left behind carbon, which joined with other molecules to make heavier materials more able to stick to the surface rather than be lost to space. These became organic molecules called tholins, which produce the red hue. There was speculation after New Horizons revealed Charon’s red pole that the cap was enriched with tholins, which could have gotten there via atmosphere transfer.
Maps made
New Horizons did more than take photos when it passed through the system in 2015. The wealth of data it sent back is still being analysed years after the probe moved deeper into the Kuiper Belt. New Horizons only directly imaged 45 per cent of the surface in daylight, meaning there are still secrets left to uncover, but by stitching together images from a pair of New Horizons’ cameras, a team from the Lunar and Planetary Institute in Texas was able to create a height map of the surveyed areas. From this, the size of surface features could be calculated, including the six-kilometre (3.7-mile) high Tenzing Montes, the moon’s highest mountain range.