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Micron‐sized dust particles detected in the outer solar system by the Voyager 1 and 2 plasma wave instruments
Author(s) -
Gurnett D. A.,
Ansher J. A.,
Kurth W. S.,
Granroth L. J.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl03228
Subject(s) - physics , interplanetary dust cloud , astrobiology , solar system , interplanetary medium , asteroid , outer planets , planet , astronomy , cosmic dust , solar energetic particles , ecliptic , astrophysics , plasma , solar wind , interplanetary spaceflight , coronal mass ejection , quantum mechanics
During the Voyager 1 and 2 flybys of the outer planets it has been demonstrated that the plasma wave instrument can detect small dust particles striking the spacecraft. In this paper, we examine the Voyager plasma wave data for dust impacts in the interplanetary medium at heliocentric radial distances ranging from 6 to 60 astronomical units (AU). The results show that a small but persistent level of dust impacts exists out to at least 30 to 50 AU. The average number density of these particles is about 2 × 10 −8 m −3 , and the average mass of the impacting particles is believed to be a few times 10 −11 g, which corresponds to particle diameters in the micron range. Possible sources of these particles are planets, moons, asteroids, comets, and the interstellar medium. Of these, comets appear to be the most likely source. The number densities are only weakly dependent on ecliptic latitude, which indicates that the particles probably do not originate from planets, moons, or asteroids. Comparisons with interstellar dust fluxes measured in the inner regions of the solar system by the Ulysses spacecraft indicate that the particles are not of interstellar origin.