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- Grün, E., et al.
(författare)
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Dust Measurements During Galileo's Approach to Jupiter and Io Encounter
- 1996
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 274:5286, s. 399-401
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Grün, E., et al.
(författare)
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Dust measurements in the Jovian magnetosphere
- 1997
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Ingår i: Geophysical Research Letters. - 1944-8007. ; 24:17, s. 2171-2174
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Tidskriftsartikel (refereegranskat)abstract
- Dust measurements have been obtained with the dust detector onboard the Galileo spacecraft inside a distance of about 60RJ from Jupiter (Jupiter radius, RJ = 71,492 km) during two periods of about 8 days around Galileo's closest approaches to Ganymede on 27 June and on 6 Sept 1996. The impact rate of submicrometer-sized particles fluctuated by a factor of several hundred with a period of about 10 hours, implying that their trajectories are strongly affected by the interaction with the Jovian magnetic field. Concentrations of small dust impacts were detected at the times of Ganymede closest approaches that could be secondary ejecta particles generated upon impact of other particles onto Ganymede's surface. Micrometer-sized dust particles, which could be on bound orbits about Jupiter, are concentrated in the inner Jovian system inside about 20RJ from Jupiter.
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| 3. |
- Grün, E., et al.
(författare)
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Galileo observes electromagnetically coupled dust in the Jovian magnetosphere
- 1998
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 103:E9, s. 20011-20022
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of dust coupled to the Jovian magnetosphere have been obtained with the dust detector on board the Galileo spacecraft. We report on data obtained during the first four orbits about Jupiter that had flybys of the Galilean satellites: Ganymede (orbits 1 and 2), Callisto (orbit 3), and Europa (orbit 4). The most prominent features observed are highly time variable dust streams recorded throughout the Jovian system. The impact rate varied by up to 2 orders of magnitude with a 5 and 10 hour periodicity, which shows a correlation with Galileo's position relative to the Jovian magnetic field. Around 20 RJ (Jupiter radius, RJ=71, 492 km) in bound a dip in the impact rate has been found consistently. At the same times, reversals by 180° in impact direction occurred. This behavior can be qualitatively explained by strong coupling of nanometer-sized dust to the Jovian magnetic field. At times of satellite flybys, enhanced rates of dust impacts have been observed, which suggests that all Galilean satellites are sources of ejecta particles. Inside about 20 RJ impacts of micrometer-sized particles have been recorded that could be particles on bound orbits about Jupiter.
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