Absorption of Energetic Protons by Saturn's Ring G.
Progress rept. for FY83,
IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
Pagination or Media Count:
In a preliminary paper on Pioneer 11 observations of energetic particles in Saturns inner magnetosphere, Van Allen et al. 1980a reported a distinctive absorption feature at a radial distance r approximately 2.82 Rs. 1 Rs Saturns equatorial radius 60,000 km. This feature was accurately the same in form, magnitude, and radial position on inbound and outbound segments of the encounter trajectory the lapse of time between the two traversals of the feature was 3.9 hours and the difference in planetocentric inertial longitudes was 178 degrees. It was labeled 1979 S3 and identified in the text as provisional evidence for a heretofore unknown satellite. In the summary table of that preliminary report it was designated as a satellite with the qualifying remark suspected to be the absorption signature of a satellite but interpretation of the signature is ambiguous. During the subsequent Saturn encounter of Voyager 1, an image was obtained of a segment of what appeared to be a faint, narrow ring of particulate matter at a radial distance of approximately 170,000 2.83 Rs. The subsequent discussion assumes that such a ring of particulate matter is the cause of the absorption feature observed by Pioneer 11 at r approximately 2.82 Rs. A restudy has been made of Pioneer 11 data on the distribution of energetic protons Ep 80 MeV in Saturns inner magnetosphere.