Discovery of Jovian dust streams and interstellar grains by the Ulysses spacecraft
Forsyth, R.; Balogh, A.; Bame, S. J.; Phillips, J. L.; Horanyi, M.; Kissel, J.; Mann, I.; Morfill, G. E.; Schwehm, G.; Hanner, M. S.; McDonnell, J. A. M.; Linkert, D.; Linkert, G.; Polanskey, C.; Grun, E.; Baguhl, M.; Fechtig, H.; Svestka, J.; Zook, H. A.; Staubach, P.; Taylor, A.; Lindblad, B. -A.; Siddique, N.
Germany, United States, United Kingdom
Abstract
ON 8 February 1992, the Ulysses spacecraft flew by Jupiter at a distance of 5.4 AU from the Sun. During the encounter, the spacecraft was deflected into a new orbit, inclined at about 80° to the ecliptic plane, which will ultimately lead Ulysses over the polar regions of the Sun1. Within 1 AU from Jupiter, the onboard dust detector2 recorded periodic bursts of submicrometre dust particles, with durations ranging from several hours to two days, and occurring at approximately monthly intervals (28 +/- 3 days). These particles arrived at Ulysses in collimated streams radiating from close to the line-of-sight direction to Jupiter, suggesting a jovian origin for the periodic bursts. Ulysses also detected a flux of micrometre-sized dust particles moving in high-velocity (>= =26 km s-1) retrograde orbits (opposite to the motion of the planets); we identify these grains as being of interstellar origin.