Saturn moon has thin atmosphere
SEP 12, 2011
DOI: 10.1063/PT.5.025570
National Geographic : On a recent close flyby of Saturn’s moon Dione, NASA’s Cassini spacecraft revealed traces of the moon’s passage left in Saturn’s magnetic field—evidence of the moon’s atmosphere. Dione doesn’t have sufficient mass to retain an atmosphere on its own, so the thin layer of air exists only because it’s constantly being replenished. The moon resides within Saturn’s belt of highly energetic particles and those particles cause Dione’s surface ice to break apart chemically, which releases molecules that become the moon’s atmosphere. Since that ice is mostly water ice, the atmosphere may be mostly oxygen. Existing data from other Cassini instruments, as well as data gathered during the next flyby on 12 December, may provide clues to whether this is so.
© 2011 American Institute of Physics
