E. Grün, ^* D. P. Hamilton, R. Riemann, S. Dermott, H. Fechtig, B. A. Gustafson, M. S. Hanner, A. Heck, M. Horanyi, J. Kissel, H. Krüger, B. A. Lindblad, D. Linkert, G. Linkert, I. Mann, J. A. M. McDonnell, G. E. Morfill, C. Polanskey, G. Schwehm, R. Srama, H. A. Zook

About a hundred dust impacts per day were detected during the first week in December 1995 by Galileo during its approach to Jupiter. These impacts were caused by submicrometer-sized particles that were just above 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 instrument 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 gravitationally concentrated near Jupiter.

E. Grün, H. Fechtig, A. Heck, J. Kissel, H. Krüger, D. Linkert, G. Linkert, R. Riemann, R. Srama, Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
D. P. Hamilton, University of Maryland, College Park, MD 20742-2421, USA.
S. Dermott and B. A. Gustafson, University of Florida, Gainesville, FL 32611, USA.
M. S. Hanner and C. Polanskey, Jet Propulsion Laboratory, Pasadena, CA 91109, USA.
M. Horanyi, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309, USA.
B. A. Lindblad, Lund Observatory, 221, Lund, Sweden.
I. Mann, Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany.
J. A. M. McDonnell, University of Kent, Canterbury, CT2 7NR, UK.
G. E. Morfill, Max-Planck-Institut für Extraterrestrische Physik, 85740 Garching, Germany.
G. Schwehm, European Space Research and Technology Centre, 2200 AG Noordwijk, Netherlands.
H. A. Zook, NASA Johnson Space Center, Houston, TX 77058, USA.
^*   To whom correspondence should be addressed.