Atmosphere containing oxygen are known to exist in the natural satellites in our solar system. For example, Europa and Ganymede, two of Jupiter's moon, is also rich in oxygen content in the atmosphere. "We have seen this before in the planet Jupiter, and we have confirmed that there is oxygen in the atmosphere of Saturn's satellite," said study leader Ben Teolis of the Southwest Research Institute in San Antonio, Texas.
NASA's Hubble Space Telescope has detected oxygen levels in the atmosphere on the moon Europa and Ganymede in the 90's. In both satellites of Jupiter, the oxygen out of the water ice surface, which is divided into hydrogen and oxygen under the original particles from Jupiter.