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| Paper: |
Structure of the Solar System's Dust Disk: Influence of Massive Bodies |
| Volume: |
324, Debris Disks and the Formation of Planets: A Symposium in Memory of Fred Gillett |
| Page: |
143 |
| Authors: |
Dermott, S.F.; Kehoe, T.J.J. |
| Abstract: |
Dust in the solar system is derived from two large reservoirs of collisionally evolved bodies: dust in the outer solar system originates from the Kuiper belt, while the solar system dust bands discovered by IRAS show that the asteroid belt is the dominant source of dust in the inner solar system. The rate of accretion of dust by the Earth inferred from the microcratering record on LDEF is shown to be consistent with an asteroidal source and we use this rate to assess the rate of accretion of dust by the other planets, and hence to discuss the probability of transporting dust from the Kuiper belt to the inner solar system.
The structure of the zodiacal cloud is determined by an interplay Between the gravitational and drag forces acting on particles in the cloud, which in turn depends upon the size of the particles. Observed asymmetries of the zodiacal cloud include: the warping of the mean plane of symmetry of the cloud due to planets in inclined orbits; an ofset of the center of the cloud from the Sun due to planets in eccentric orbits; and clumping due to resonant trapping of particles by planets. The injection of dust into the zodiacal cloud is a stochastic process and large variations in the optical depth of the cloud are produced by the total disruption of both large asteroids and large comets.
The catastrophic fragmentation and dispersal of the large asteroids that were the precursors of the Hirayama asteroid families produced numerous smaller asteroids that, with low probability, may have eventually impacted the Earth. However, these colossal, family-producing collisional events would have also given rise to waves of dust that would have swept through the inner solar system on timescales of tens of thousands to millions of years. The Earth could not have avoided these waves of dust and it is of interest to speculate on the possible climatic consequences of this interaction. |
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