37th DPS Meeting, 4-9 September 2005
Session 17 Dust, Impacts and Earth Atmosphere
Poster, Monday, September 5, 2005, 6:00-7:15pm, Music Recital Room

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[17.04] Dynamics and Distribution of Interplanetary Dust

S.I. Ipatov (University of Maryland, USA), J.C. Mather (NASA/GSFC, USA)

We integrated the orbital evolution of 12,000 asteroidal, cometary, and trans-Neptunian dust particles, under the gravitational influence of planets, Poynting-Robertson drag, radiation pressure, and solar wind drag (Annals of the New York Academy of Sciences, v. 1017, 66-80, 2004; Advances in Space Research, in press, 2005). The orbital evolution of 30,000 Jupiter-family comets (JFCs) was also integrated (Annals of the New York Academy of Sciences, v. 1017, 46-65, 2004). For asteroidal and cometary particles, the values of the ratio \beta between the radiation pressure force and the gravitational force varied from <0.0004 to 0.4 (for silicates, such values correspond to particle diameters between >1000 and 1 microns). The considered cometary particles started from comets 2P, 10P, and 39P. The probability of a collision of an asteroidal or cometary dust particle with the Earth during a lifetime of the particle was maximum at diameter about 100 microns; this is in accordance with cratering records. Our different studies of migration of dust particles and small bodies testify that the fraction of cometary dust particles of the overall dust population inside Saturn's orbit is considerable and can be dominant: (1) Some JFCs can reach orbits entirely located inside Jupiter's orbit and remain in such orbits for millions of years. Such former comets could disintegrate during millions of years and produce a lot of mini-comets and dust. (2) The spatial density of migrating trans-Neptunian particles near Jupiter's orbit is smaller by a factor of several than that beyond Saturn's orbit. Only a small fraction of asteroidal particles can migrate outside Jupiter's orbit. Therefore cometary dust particles are needed to explain the observed constant spatial density of dust particles at 3-18 AU from the Sun. (3) Comparison of the velocities of zodiacal dust particles obtained in our runs with the observations of velocities of these particles made by Reynolds et al. (Ap.J., 2004, v. 612, 1206-1213) shows that only asteroidal dust particles cannot explain these observations, and particles produced by high-eccentricity comets (such as Comet Encke) are needed for such explanation. Several our recent papers are presented on astro-ph.

The author(s) of this abstract have provided an email address for comments about the abstract: sipatov@umd.edu

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