what are the composition of this moon?
The plumes' salty composition (-Na, -Cl, -CO) indicates that the source is a salty subsurface ocean.
Enceladus
The plumes' salty composition (-Na, -Cl, -CO) indicates that the source is a salty subsurface ocean.

which one of saturn's moons has water Moon Enceladus who discovered this moon? William Herschel and when did this person discover? August 28, 1789 how did it get its name? It is named after the giant Enceladus of Greek mythology
wiki:19540303
Enceladus [SEP] Composition
The "Cassini" spacecraft flew through the southern plumes on several occasions to sample and analyze its composition. As of 2019, the data gathered is still being analyzed and interpreted. The plumes' salty composition (-Na, -Cl, -CO) indicates that the source is a salty subsurface ocean. The INMS instrument detected mostly water vapor, as well as traces of molecular nitrogen, carbon dioxide, and trace amounts of simple hydrocarbons such as methane, propane, acetylene and formaldehyde. The plumes' composition, as measured by the INMS, is similar to that seen at most comets. "Cassini" also found traces of simple organic compounds in some dust grains, as well as larger organics such as benzene (), and complex macromolecular organics as large as 200 atomic mass units, and at least 15 carbon atoms in size.