DUST MEASUREMENTS DURING GALILEOS APPROACH TO JUPITER AND IO ENCOUNTER

About a hundred dust impacts per day were detected during the first we ek in December 1995 by Galileo during its approach to Jupiter, These i mpacts were caused by submicrometer-sized particles that were just abo ve the detection limit. After the closest approach to Io on 7 December , impacts of these small particles ceased, This effect is expected for dust grains emitted from Io that exit the field of view of the instru ment after the flyby. The impact rate of bigger micrometer-sized dust grains continued to increase toward Jupiter. These dust particles are in orbit about Jupiter or are interplanetary grains that are gravitati onally concentrated near Jupiter.