THE EXOSPHERIC SYSTEMS OF SATURNS RINGS

Because of collisional interaction with interplanetary meteoroids, the ring system of Saturn is supposedly a major source of neutral gas cloud in the inner saturnian system. We consider some new features brought about by the asymmetric impact geometry of the ring-meteoroid interaction. An assessment is also attempted on the most likely spatial structure and neutral gas number density distribution of the ring exosphere. A meteoroid-impact gas production rate of 5 x 10(27) molecules/sec which is a factor of 100 lower than the maximum value previously derived is preferred in the present work. The maximum density of the H2O molecules in the vicinity of the B ring is about 100 cm(-3). Finally, because of gas-surface interaction in the ring environment a thin disc of oxygen molecules might form as one of the major components of the ring exosphere with a density of about 3000 cm(-3). This molecular oxygen cloud, if it exists, would in turn supply a flux of oxygen atoms via photodissociation to the orbital region of the icy satellites. (C) 1995 Academic Press, Inc.