Equatorial surface temperatures on the Galilean satellites range from 80 K (night) to 155 K (the subsolar point on Callisto). Magnetosphere The outer region of the magnetosphere contains a hot plasma consisting primarily of hydrogen, oxygen, and sulfur ions. The hot plasma generally flows in the corotation direction out to the boundary of the magnetosphere. Beyond about 160 R_J, the hot plasma streams nearly antisunward. Outbound the spacecraft experienced multiple magnetopause crossings between 204 R_J and 215 R_J. The abundance of oxygen and sulfur relative to helium at high energy increases with decreasing distance from Jupiter. Measurements of high energy oxygen suggest that these nuclei are diffusing inward toward Jupiter. The ultraviolet emission from the Io plasma torus was twice as bright as four months earlier and the temperature had decreased by 30 percent to 60 000 K. The low-frequency (kilometric) radio emissions from Jupiter have a strong latitude dependence and often contain narrowband emissions that drift to lower or higher frequencies with time. A complex magnetospheric interaction with Ganymede was observed in the magnetic field, plasma, and energetic particles up to about 200 000 kilometers from the satellite. [3]Adapted from a summary prepared by E. C. Stone and A. L. Lane for the Voyager 2 Thirty-Day Report. [Illustration: A new inner satellite of Jupiter, provisionally designated 1979J1, was discovered by David Jewitt and Ed Danielson of Caltech in these Voyager 2 ring photographs.] [Illustration: In a 15-second exposure with the wide-angle camera, the edge-on ring shows as a faint line, and the satellite is the dot indicated by the arrow. [260-807]] [Illustration: In a narrow angle 96-second exposure, the motion of the satellite can be seen. Again, the faint band is the ring, blurred by camera motion, and the arrow indicates the streak due to the satellite. A star streak is located above and to the left of the satellite; note that the length and angle of the two trails are different, owing to satellite motion. [P-22172]] A New Satellite