Charon (moon)
largest natural satellite of Pluto
Charon ( KAIR-on, -ən or SHARR-ən), formal designation (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto. It has a mean radius of 606 km (377 mi). Charon is a planetary-mass moon and the sixth-largest known trans-Neptunian object after Pluto, Eris, Haumea, Makemake, and Gonggong. It was discovered in 1978 at the United States Naval Observatory in Washington, D.C., using photographic plates taken at the United States Naval Observatory Flagstaff Station (NOFS).
With half the diameter and one-eighth the mass of Pluto, Charon is a very large moon in comparison to its parent body. Its gravitational influence is such that the barycenter of the Plutonian system lies outside Pluto, and the two bodies are tidally locked to each other. The dwarf planet systems Pluto–Charon and Eris–Dysnomia and the dwarf planet candidate system Salacia–Actaea are the only known examples of mutual tidal locking in the Solar System, though it is likely that Orcus–Vanth is another.
The reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be essential ingredients of life. These tholins were produced from methane, nitrogen, and related gases which may have been released by cryovolcanic eruptions on the moon, or may have been transferred over 19,000 km (12,000 mi) from the atmosphere of Pluto to the orbiting moon.
The New Horizons spacecraft, the only probe to visit the Pluto system, approached Charon to within 27,000 km (17,000 mi) in 2015.
The public source identifies “Charon (moon)” as largest natural satellite of Pluto. This brief keeps that definition visible, then builds a research path around Charon, moon and largest.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 10, 2026. The linked authority identifier is Q6604. VIAF identifies the subject as 315160640. The Library of Congress control number is sh95007255. 2 of 2 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1978 and 2015.
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This entry incorporates text from “Charon (moon)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.