In which year was the moon, on which the volcanic feature Reiden Patera is located, discovered ?
Io (moon) Io (Jupiter I) is the innermost of the four Galilean moons of the planet Jupiter. It is the fourth-largest moon, has the highest density of all the moons, and has the least amount of water of any known astronomical object in the Solar System. It was discovered in 1610 and was named after the mythological character Io, a priestess of Hera who became one of Zeus's lovers.
Rayya (crater) Rayya is an impact crater on the southern hemisphere of Saturn's moon Enceladus. Rayya was first observed in "Cassini" images during that mission's March 2005 flyby of Enceladus. It is located at 32.5° South Latitude, 178.4° West Longitude, and is 9 kilometers across. "Cassini" observed numerous criss-crossing sets of fractures cutting across Rayya, forming canyons several hundred meters deep along the crater's rim.