ESA Science & Technology30-Jun-2005 16:44:02

Beyond the Heliosphere

Size Distribution and Dynamics of Interstellar Dust in the Planetary System

Analysis of interstellar dust grains inside the heliosphere, a key Ulysses discovery, provides a new window for the study of diffuse interstellar matter. Ulysses discovered dust particles to be more massive (> 10-13 g) and found smaller grains to be less abundant than the 'classical' interstellar grains that are observed by astronomical means. Calculations show that, depending on the polarity of heliospheric magnetic field, 0.1 micron-sized and smaller particles have great difficulty entering the heliosphere owing to their interaction with the HMF. The solar magnetic polarity reversal in 2001-2002 is expected to affect the distribution and properties of interstellar dust in the heliosphere, concentrating the dust toward the Sun and into the inner heliosphere.

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