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In Situ Measurements of Cosmic Dust

2001; Springer International Publishing; Linguagem: Inglês

10.1007/978-3-642-56428-4_7

2196-9698

E. Grün, M. Baguhl, H. Svedhem, H. A. Zook,

Astrophysics and Star Formation Studies

In-situ measurements of cosmic dust provide information on the spatial and orbital distributions, and on the physical and chemical properties of dust in interplanetary space. Pioneers 8 through 11, Helios, Galileo and Ulysses spaceprobes measured interplanetary dust from 0.3 to 18 AU distance from the Sun. The Earth satellites HEOS, Hiten, as well as other spacecraft, determined the flux of micrometeoroids at 1 AU. The size distribution from a few micrometer to millimeter range was also characterized by analysis of lunar micro craters and later verified by near-Earth satellites like LDEF. Distinctly different populations of dust particles exist throughout the solar system. In the inner solar system, out to about 3 AU, zodiacal dust particles are observed by in-situ detection from spaceprobes. These particles orbit the Sun on low inclination (i < 30°) and moderately eccentric (e < 0.6) orbits. Their spatial density falls off somewhat faster than the inverse of the solar distance. In addition, particles on highly eccentric orbits have been recorded in the inner solar system. β-meteoroids leave the solar system on unbound (hyperbolic) orbits because of the action of solar radiation pressure and electromagnetic forces. They have been observed by the Pioneers 8, 9, Hiten, and by the Ulysses spacecraft. Pioneers 10 and 11 showed that dust particles on high inclination or even retrograde trajectories compose much of the population of big dust particles (> 10 μm) outside about 3 AU. The dust detectors onboard the Ulysses and Galileo spaceprobes identified micrometer sized interstellar dust sweeping through the solar system. Within a distance from Jupiter of about 2 AU Ulysses and Galileo observed streams of tiny grains originating from within the jovian system.